There was agony for Matteo Berrettini as he was forced to retire in his first match of the ATP Finals against Alexander Zverev on home soil.

Italian Berrettini appeared to suffer an abdominal injury when trailing 1-0 in the second set after Zverev won the first 7-6 (9-7) in their opening Red Group match in Turin on Sunday.

Sixth seed Berrettini dropped his racket and put his head in his hands as he grimaced after crashing a forehand into the net and underwent lengthy treatment to his left side.

The world number seven attempted to continue, but was clearly in pain as he served and duly brought the contest to an end at the Pala Alpitour.

Berrettini cut an emotional figure and was embraced by Zverev before being given a great ovation as he trudged off the court, with his opponent standing to applaud.

Zverev had saved two set points in the opening set and came from 5-3 down in the breaker to edge in front before the match came to a premature end.

WINNERS/UNFORCED ERRORS 

Zverev – 21/9
Berrettini– 16/23

ACES/DOUBLE FAULTS 

Zverev – 10/1
Berrettini – 5/0

BREAK POINTS WON 

Zverev – 0/5
Berrettini – 0/2

Lewis Hamilton acknowledged his stunning fightback victory at the Sao Paulo Grand Prix felt as good as his first in Formula One.

The Mercedes driver saw his Friday qualifying session result ruled out due to a DRS infringement, meaning he started the sprint race in last, but went from 20th to fifth, only for a five-place grid penalty to mean he started 10th on Sunday.

However, the Briton delivered a memorable win, gaining eight places early on and overtaking Max Verstappen with 12 laps remaining.

The reigning world champion cut Verstappen's lead in the battle for the title to 14 points with three races to go.

"It feels like a first as I haven't had a win for a long time," Hamilton said.

"I never thought we would close the gap like we did today when things just seemed to be going against us.

"It just shows you should never give up whatever you are facing. You need to keep pushing, keep tumbling and never ever stop fighting. That's what I have done this weekend.

"The team did an amazing job and Valtteri Bottas did a great job to [finish third and] get as many points as possible.

"I just pushed as fast as I could, but from last on the grid and another five-place penalty this is my hardest weekend I have had [this season]."

Hamilton has now won 17 races in the Americas (seven in Canada, six in the United States, two in Brazil and two in Mexico).

It means he overtakes the legendary Michael Schumacher as the driver with the most F1 victories across the four nations.

He dedicated the victory to his father Anthony and to the Brazilian fans who supported him at Interlagos.

He added: "My dad reminded me of when I was in F3 in Bahrain around 2004, when I started last and finished first - so this one is for my dad.

"I am so grateful for the incredible support I have had this weekend. I have not had this much support since Silverstone, and since then it has been really difficult.

"To hear these fans throughout the weekend has been humbling. I have been saying 'obrigado Brasil' because I am so grateful."

Next up is the Qatar Grand Prix and Red Bull driver Verstappen vowed to finish the campaign strongly as he eyes his first F1 title.

He said: "We tried everything we could today, it was a good battle but at the end we missed a little pace. But it was good fun.

"We still have a decent lead so today was a bit of damage limitation. I'm confident, in the coming races we will come back stronger."

The Women's Tennis Association (WTA) has opened an investigation into Peng Shuai's sexual assault allegations against a former China leader.

Shuai, 35, posted on Chinese social media site Weibo allegations against Zhang Gaoli – the ex-vice premier and member of the Chinese Communist Party's Politburo Standing Committee – claiming he had forced her to have sexual relations with him.

In the post, published on Tuesday before subsequently being deleted, the 2013 Wimbledon doubles champion alleged that the pair had extramarital relations and she had developed feelings for him.

All of Peng's content has since been removed from Weibo and numerous reports suggest she has not been seen in recent days.

The WTA's chairman Steve Simon addressed the matter on Sunday in a statement that said: "The recent events in China concerning a WTA player, Peng Shuai, are of deep concern. As an organisation dedicated to women, we remain committed to the principles we were founded on – equality, opportunity and respect.

"Peng Shuai, and all women, deserve to be heard, not censored. Her accusation about the conduct of a former Chinese leader involving a sexual assault must be treated with the utmost seriousness.

"In all societies, the behaviour she alleges that took place needs to be investigated, not condoned or ignored. We commend Peng Shuai for her remarkable courage and strength in coming forward.

"Women around the world are finding their voices so injustices can be corrected.

"We expect this issue to be handled properly, meaning the allegations must be investigated fully, fairly, transparently and without censorship.

"Our absolute and unwavering priority is the health and safety of our players. We are speaking out so justice can be done."

Daniil Medvedev got his ATP Finals title defence started in impressive fashion as he came from behind to defeat Hubert Hurkacz.

In the first match of the singles draw in Turin, Medvedev overcame a difficult start to ultimately cruise to a 6-7 (5-7) 6-3 6-4 win over the Wimbledon semi-finalist.

Hurkacz showed flashes of his quality, but made 17 unforced errors to Medvedev's eight as the second seed did not offer up a single break point.

Medvedev, who did not win a match in his debut at the tournament in 2019, tops the Red Group, which also includes Alexander Zverev and Matteo Berrettini.

Hurkacz's aggressive net play saw him make the breakthrough in the first set tie-break, with neither player having offered up a single break point during the opener.

The Pole did lose three successive points to go from 6-2 up to 6-5 before eventually taking the set at the fourth time of asking.

Yet Medvedev controlled things in set two, breaking early to nose himself ahead, with Hurkacz losing the composure he had shown in the opening exchanges.

Medvedev took the set at the third opportunity, and Hurkacz's frustration followed into the decider as the Russian breezed into a 2-0 lead.

Hurkacz offered a reminder of his class with a deft volley that left Medvedev with too much to do, yet the world number nine slipped up with a similar shot in the next game to give his opponent the edge.

Despite battling back from 0-30 down to hold serve and keep himself in the match, Hurkacz did not have an answer for Medvedev's power, as the world number two served out a relatively routine win.

WINNERS/UNFORCED ERRORS 

Medvedev – 31/8
Hurkacz – 31/17

ACES/DOUBLE FAULTS 

Medvedev – 15/1
Hurkacz – 12/0

BREAK POINTS WON 

Medvedev – 2/4
Hurkacz – 0/0

Roger Federer is unlikely to compete at next year's Australian Open, but the 20-time grand slam champion is not yet thinking of retirement, so says coach Ivan Ljubicic.

Federer has endured an injury-hit two seasons. After reaching the semi-finals at the 2020 Australian Open, the Swiss star underwent knee surgery, with a complication in his recovery leading him to take the rest of the year off.

That prolonged rehabilitation, plus the strict COVID-19 regulations in Australia, meant he did not compete in Melbourne earlier this year, but Federer returned to the ATP Tour in Qatar in March.

He went on to reach the last 16 of the French Open, losing to Matteo Berrettini, and the quarter-finals at Wimbledon, where he went out to Hubert Hurkacz.

However, he has not featured since then after undergoing surgery for another knee problem sustained on the grass-court circuit.

With Australia's tight coronavirus restrictions still in place, it is unclear whether Novak Djokovic, who has tied level with Federer and Rafael Nadal on 20 major wins, will compete in Melbourne early in 2022.

Nadal, too, has not yet confirmed his participation, and with Ljubicic suggesting Federer will not be fit in time, all three greats could be missing from next year's first grand slam.

"I think there are very few chances, he is still recovering and knowing him he wants to be sure he can play to win the tournament and be at 100 per cent," Ljubicic said.

"So I think Australian Open is not a real possibility right now. But he will go step by step because he is 40 years old and he needs to be patient. He cannot recover as quickly as he used to."

Despite doubts over his participation in Australia, and the time he has spent away from the court in the past two years, Federer is not considering retirement just yet.

"We have spoken and I can guarantee he wants to return playing tennis," Ljubicic added. "When he will decide to stop, he will retire, but I don't think it's going to happen all of a sudden."

Ljubicic is only two years Federer's senior and, as a player, reached a high of world number three back in 2006. He has coached Federer since 2016, helping him to three grand slam titles.

"Many times I found myself wondering what am I doing here? But in the end I hope and I think I was able to help him in those few moments he needed in the right way at the right time," Ljubicic said.

"There's always a risk when you meet your idol in person, as you may discover something you don't like, but with him, it is not the case. With him, there are no risks, he really is an extraordinary person. 

"I have been lucky enough to live beside him in the past six years and I enjoyed it very much. I really have fun with him. Is it difficult? No, it's just beautiful. When we discuss tennis, I ask myself: why he is paying me?"

Coach J. B. Bickerstaff lauded Evan Mobley's "will to win" after the rookie "stepped up big" in the Cleveland Cavaliers' stunning comeback victory against the Boston Celtics.

The Cavaliers moved to 9-5 with their sixth win in seven games on Saturday, making this their best start to a season since 2016-17 – a year in which LeBron James led the team to the third of four straight NBA Finals visits.

This latest 91-89 triumph was particularly impressive as Cleveland trailed by 19 points when Mobley returned to the game late in the third quarter.

"We keep talking about chemistry and bonding and belief in one another, and that was on full display tonight," said Bickerstaff. "That's the only way you can explain it.

"There's no basketball reason we should have won that game, but there was a collective spirit that refused to allow us to lose that game. That's what we keep talking about brewing in that locker room.

"Don't get me wrong, some guys made critical plays and carried their weight, but it's the spirit of that basketball team, that has that fight in them, that won't give up."

Several of those critical plays belonged to third overall pick Mobley, who finished with 19 points, nine rebounds, three blocks and two steals in 40 minutes. Of those, 12 points, two blocks and a steal came in the fourth quarter as he played its entirety.

No player in the NBA scored more clutch points than Mobley's six on Saturday, albeit tied with the Celtics' Jayson Tatum – who the Cavs man was asked to stop.

"It's the will to win basketball games," Bickerstaff said of Mobley's best trait. "Literally the only thing that matters to him is: how do I help this team win?

"Not only was it the block, but it's the free throws, it's the baseline jumper, it's the post move to get to the finish. It was an array of different things.

"Then at the end of the game, we had him on Jayson Tatum. We put him on the other team's best player. Whatever it takes to win, he's willing to do it.

"He's not satisfied with these small victories or these small moments. He understands what he wants long-term, and he understands that in order to get there, you've got to do it every night.

"He didn't start out blazing, he was working his way through it in the first half. Then as the game got going, he found his way. And when it was clutch time, he stepped up big."

Mobley has quickly proven a threat from anywhere on the court in his short time in the NBA but is especially effective at the rim, making 70.1 per cent of his attempts.

In fact, 36.8 per cent of his successful field goal attempts have been dunks, with his 32 made dunks ranking joint-third in the NBA. Team-mate Jarrett Allen's 47 lead the way, while no team can rival the Cavaliers' combined 98.

Allen's latest dunk put Cleveland up with 35.9 seconds left against Boston, and Darius Garland said: "It's super fun, just bringing all the crowd into it, the arena gets pumped up. I like seeing it a lot."

Bickerstaff, whose team rank fourth in the league for points in the paint (672), added: "We want to put pressure on the rim, and however we can do that, we'll take it.

"Jarrett is an elite lob threat, and when you put that much pressure on the rim, defenses get concerned. Even if it's only two points, it's an emphatic two points, and defenses don't like that. Then they start to collapse and we've got wide open threes.

"We've got guys who we feel like can dominate the paint – that's our objective: offensively, we want to dominate the paint as much as we can."

Joel Embiid should be back in the lineup soon, but the Philadelphia 76ers need to figure some things out on defence in the meantime. 

Philadelphia fell 118-113 to the Indiana Pacers on Saturday after digging a large first-half hole as the 76ers proved unable to stop anyone from scoring. 

Indiana shot 67.4 per cent from the floor in the opening half, embarking on a 15-0 run beginning late in the first quarter and leading by as many as 20 before the break. 

"Listen, we didn’t deserve to win tonight," Philadelphia head coach Doc Rivers told reporters. "They shot 57 per cent from the field, 67 I think at half-time, and we cooled them off a little bit.

"They played harder. They beat us in transition, I think they had 18 transition points in the first half, we cut it in the second half to make the game manageable, but when you’re on the road, and you get down 20 and you dig yourself a hole, it’s hard coming back, it is.

"Give them credit. They were better prepared. They were the better team tonight."

It was the fourth successive loss for the 76ers as Embiid missed his fourth consecutive game after testing positive for COVID-19 on Monday. 

Matisse Thybulle also missed his fifth game in a row due to health and safety protocols, and Tyrese Maxey said the void is significant. 

"They’re like defensive bail-outs," Maxey said. "When you make a mistake, they’ll cover it up because they’re just special guys. You can go for a gamble, miss it, Matisse will cover it up and get a block.

"Joel’s seven-foot at the rim, you get blown by, he’s blocking it or he’s challenging shots. It’s hard for offensive players to score on them. We’ve got to be collectively more solid without those guys." 

In a stretch when the short-handed 76ers cannot afford any letdowns, Maxey also said the team's "competitive nature slipped" in the first half, "and that's one thing we can never let slip". 

The Cleveland Cavaliers scored just nine points in the first half and trailed much of the game before rallying to stun the Boston Celtics 91-89 on Saturday. 

Cleveland (9-5) trailed by as many as 19 with 3:05 left in the third quarter before roaring back with a 24-4 run to set up a frenzied finish that featured seven ties and five lead changes in the last seven minutes of the game. 

Darius Garland led the Cavaliers with 22 points, including two critical free throws with 9.4 seconds left that provided the final margin. He had kept the home team in the game single-handedly earlier in the evening, making 10 of Cleveland's 12 first-half field goals. 

One night after dropping 38 points in a home win against the Milwaukee Bucks, Dennis Schroder had a game-high 28 for on Saturday, but he missed a potential game-tying shot at the buzzer. 

The Celtics (6-7) were foiled in their attempt to get over .500 for the first time this season but will have a chance to get back to even with a rematch Monday in Cleveland. 

The Cavaliers have won six of their last seven games. 

Clippers win seventh straight

After a 1-4 start to the season, the Los Angeles Clippers picked up their seventh straight win with a 129-102 defeat of the Minnesota Timberwolves (4-8). The Clippers (8-4) put the game away by half-time, building a 70-43 lead as Reggie Jackson scored 18 of his 21 points before the break. Paul George led all scorers with 23 and Anthony Edwards topped the Timberwolves with 21. 

The Washington Wizards (9-3) continued their hot start even without star Bradley Beal, rolling to a 104-92 victory over the Orlando Magic (3-10) behind 23 points, 11 rebounds and six assists from Spencer Dinwiddie and 20 points, six rebounds and seven assists off the bench by Montrezl Harrell. Beal missed the game to mourn the death of his grandmother. 

The New Orleans Pelicans opened up a lead of as many as 22 points in the first half and held on for a 112-101 defeat of the Memphis Grizzlies (6-7). The victory snapped a nine-game losing streak for the Pelicans (2-14) as they continue to play without Zion Williamson. 

Jazz continue to struggle

The Utah Jazz (8-5) lost for the fourth time in five games, falling 111-105 at home against the Miami Heat (8-5). The visitors built a 95-69 lead after three quarters and cruised the rest of the way as Tyler Herro led all scorers with 27 points. Utah made just 35 of 85 shots from the field (41.2 per cent), including 17 of 53 from three-point range (32.1 per cent).

Top seed Aryna Sabalenka bounced back from a disappointing defeat in her opening match at the WTA Finals to rally past Iga Swiatek in Guadalajara. 

Sabalenka steadied herself after dropping the opening set and prevailed 2-6 6-2 7-5 Saturday to keep alive her hopes of reaching the semi-finals in her maiden appearance at the event. 

Swiatek, the youngest player in the field at age 20, broke Sabalenka in her final two service games of the first set but could not maintain the momentum as the Belarusian returned the favour in the second. 

Sabalenka entered Saturday with a 9-13 record in three-set matches compared to 35-4 in two-setters but maintained her nerve after the pair traded breaks early in the decider. 

The world number two broke Swiatek to take a 6-5 lead, then served the final game out at love for the victory. 

With Sabalenka's win, Paula Badosa advances to the semi-finals as winner of the group, while the winner of Monday's match between Sabalenka and Maria Sakkari also will advance. Swiatek is out of contention for the semis. 

History is not necessarily on Sabalenka's side, as the top seed has failed to advance from the group stage at three of the past five WTA Finals. 

WINNERS/UNFORCED ERRORS 

Sabalenka – 16/27
Swiatek – 15/18

ACES/DOUBLE FAULTS 

Sabalenka – 8/16
Swiatek – 2/3

BREAK POINTS WON 

Sabalenka – 4/7
Swiatek – 3/7

Lewis Hamilton has reason for optimism in Sunday's Brazilian Grand Prix despite starting from the 10th position. 

The Mercedes driver roared up 15 places over just 24 laps in Saturday's sprint, finishing fifth after starting 20th following a DRS infringement in qualifying Friday. 

A five-place grid penalty for taking a new engine will put him further behind front-row starters Valtteri Bottas and Max Verstappen in the main event but Hamilton's speed from the back Saturday should stand as a warning to his rivals. 

"It's not over yet," Hamilton said over the radio after the sprint. 

He later told reporters: "Really it was just the mental state of mind that I went into, which was just never give up, keep pushing, still I rise, you can do this.

"Because it was really difficult to swallow the result that we got [the penalty] but we won’t let that hold us back.

"Now I’ve got to start focusing on tomorrow. I’ll give it everything. It’s a much longer race tomorrow so hopefully we can get further." 

Hamilton can also take solace in Verstappen finishing second to Bottas in the sprint after starting first following Hamilton's penalty. 

While Bottas went with soft tyres, Verstappen opted for medium and had a gear sync issue that also hung him up, a double blow to the Red Bull driver's hopes. 

"All-in-all that didn’t work out for me," Verstappen said of his Saturday setup. "Then of course, I dropped to third on the first lap but then after that, I mean the pace was fine but you can’t overtake around here.

"The tyres just very quickly overheat and you are stuck – especially when the cars are closely matched on pace: there’s not much you can do in the sprint without a pit stop. So, I just sat behind basically."

With significantly hotter conditions expected Sunday, Verstappen was not sure how that might change the setup. 

"Yeah, let’s see," he said. "It’s going to be quite a bit warmer. I mean, today was also quite a late race, so hopefully that will be a bit better for us – but it’s a bit difficult to say at the moment."

Verstappen is 21 points clear of Hamilton in the standings as he bids to end Mercedes' seven-year drivers' championship monopoly and deny the Briton an eighth world title.

Paula Badosa made it two wins from two at the WTA Finals as she saw off a battling Maria Sakkari in straight sets.

In-form Badosa triumphed 7-6 (7-4) 6-4 in two hours and four minutes to win her eighth straight match, having come into the tournament on the back of her triumph at Indian Wells.

Permutations for the last round of group-stage matches in Guadalajara will become clearer after Aryna Sabalenka has taken on Iga Swiatek later on Saturday.

But after beating Sabalenka and Sakkari without dropping a set, Badosa looks all but certain to reach the semi-finals on her debut appearance at the event.

In the first meeting between the two players, Badosa led 5-2 only to be forced into an opening-set tie-break by Sakkari, who then undid her hard work by losing the first four points of the breaker, with the Spaniard ultimately sealing the first set courtesy of a fine forehand.

Badosa struck first again with a break early in the second set and although Sakkari was able to level matters at 4-4, her opponent broke decisively immediately after before serving it out, converting her third match point with a backhand winner.

WINNERS/UNFORCED ERRORS 

Sakkari – 25/49
Badosa – 23/22

ACES/DOUBLE FAULTS 

Sakkari – 1/4
Badosa – 10/6

BREAK POINTS WON 

Sakkari – 2/5
Badosa – 3/12

Carlos Alcaraz rounded off a superb 2021 by claiming the ATP Next Gen Finals title with a straight-sets victory over Sebastian Korda.

Alcaraz produced a performance in keeping with a breakthrough year for the Spaniard, prevailing 4-3 (7-5) 4-2 4-2 in Milan.

It marked Alcaraz's 32nd tour-level win of a year that also saw him reach the quarter-finals of the US Open.

The 18-year-old is the youngest player to claim 32 wins in a year since 1992, when Andrei Medvedev achieved the feat at 18.

Alcaraz faced five break points in his first two service games but had to stave off just one more the rest of the way.

He did fall 0-30 behind when serving for the match, yet Korda could not deny Alcaraz his second Tour title of the year.

"It is amazing," Alcaraz said in his on-court interview. "To be able to win this tournament means a lot to me.

"I am so excited right now and emotional. I was very, very nervous at the start.

"I had to be calm to save the break points. I know Korda is serving very well, so I had to play my best in those moments.

"It went 0-30 on my serve. So I had to be focused in that moment and I had to stay calm. It was really, really tough."