World number 18 Reilly Opelka is through to the semi-final of the US Men's Clay Court Championships in Houston after defeating qualifier Gijs Brouwer 6-3 7-5.

The giant American, who measures in at six-foot-11, was terrific in the opening set, winning 84 per cent of his successful first serves (16-19) and allowing no break point opportunities.

The second set was much more competitive, as Brouwer broke first to go up 3-1, but Opelka answered instantly and then grabbed the match-winning break when 6-5 up to avoid a tie-breaker.

Opelka will face a fresh Nick Kyrgios in the semi-final after the Australian was gifted a walkover win against Michael Mmoh due to injury.

In a clash between two top-five seeds, world number 29 Christian Garin got the better of world number 13 Taylor Fritz 6-2 6-7 (5-7) 6-3.

What made Garin successful in the first and third sets was his return game, winning more than half of his return points in those sets combined (26-51).

Fritz had chances to get back into the game, but Garin saved 11 of 14 break point opportunities, including six of seven in the deciding third set.

Garin will play American John Isner in the semi-final after Isner triumphed in a three-set battle against Frances Tiafoe 6-4 2-6 6-3.

Isner's trademark serve was inconsistent, and abandoned him in a grim second-set performance, winning just 11 of 21 service points on his way to getting broken twice to allow Tiafoe to force the match into a third frame.

In Isner's two successful sets, he won more than 80 per cent of his first serves (35-41), and allowed no break point opportunities in the third.

Taylor Fritz saw his way past Alejandro Tabilo to advance to the quarter-finals at the US Men's Clay Court Championships, winning 6-1 6-4 on Thursday.

Fresh off his maiden ATP 1000 title at Indian Wells and fourth-round run in Miami, the American world number 13 needed just 62 minutes to win in straight sets, in his first clay court match for the season.

Fritz's serve was not particularly secure, though, with the unseeded Tabilo converting on only one of six break point attempts. Fritz was more efficient and assertive when opportunities presented on the other hand, taking two of three break point chances on Tabilo's serve while winning 12 out of 19 points returning on his second serve.

Despite the Chilean world number 100 fighting back to 4-4 from 3-0 down in the second set, Fritz steadied to close out the match.

"I felt like tonight was going to be a really tough match, given he's done really well on clay," Fritz said post-match. "It was my first match [on clay]. I'm pretty happy with how I played. I can't complain, I got out of that pretty solid."

Fritz will now face another Chilean, fifth seed and defending champion Cristian Garin, who came back from a set down to defeat Jordan Thompson 3-6 6-3 6-3.

Entering the Houston event on a five-match losing streak, Garin has come from behind in back-to-back matches to win.

Sixth seed Frances Tiafoe also went the distance on Thursday, earning a 5-7 7-5 7-6 (7-4) win over Uruguayan Pablo Cuevas.

With neither garnering break point chances in the third set, Tiafoe finally created breathing room by winning four straight points at 2-2 in the deciding tie-break, before closing out the match.

It sets up an all-American quarter-final with John Isner, who defeated Steve Johnson 6-7 (1-7) 7-6 (7-4) 6-3 in Thursday's final game.

Nick Kyrgios made his return to clay with a win on Tuesday, defeating Mackenzie McDonald 4-6 6-3 6-4 at the US Men's Clay Court Championships in Houston.

It was the first time Kyrgios had played on clay since his infamous meltdown at the Rome Masters in 2019, where he threw a chair across the court and walked off, handing Casper Ruud a win by default.

After a meandering first set, the Australian world number 94 sparked into life when he saved the first of two break points with a second serve ace in the third game of the second. From there, Kyrgios opened up his shoulders and became more assertive from the baseline, as well as serving 18 aces in the closing two sets.

While again admitting clay is not his favourite surface, the 26-year-old was nevertheless pleased by the manner of the win against McDonald.

"He [McDonald] beat me in Washington where I used to play pretty well, and he's a tricky one because he doesn't make too many errors, and clay's obviously not my preferred surface," he said post-match.

"I just served really well, and just started playing more aggressive and found another gear. I would slip and slide a little bit, but my game actually suits the clay quite well."

While US seventh seed Tommy Paul secured a walkover 6-7 (4-6) 7-6 (7-5) 3-2 win against Peter Gojowczyk, Chilean fifth seed and defending champion Cristian Garin also came from a set down to beat Jack Sock 4-6 6-3 7-5.

American sixth seed Frances Tiafoe faced relatively simpler work, defeating unseeded countryman Marcos Giron in straight sets 6-4 6-4.

Two all-American matches also opened play in Houston on Tuesday, with JJ Wolf securing a 6-4 6-4 win over eighth seed Jenson Brooksby in the first, and Steve Johnson defeating Denis Kudla 6-3 4-6 6-4.

Defending champion Cristian Garin was victim of the biggest shock of Tuesday's play at the Rio Open.

Fifth seed Garin – winner of the most recent edition in 2020 – exited a second consecutive tournament at the first-round stage after he was humbled by Federico Coria.

Coria had defeated the fifth seed, Dusan Lajovic, at last week's Argentina Open, too, but was particularly impressive on Tuesday.

A stunning 6-2 6-0 win was sealed in an hour and 16 minutes.

Coria fended off two break points midway through the first set and then won the remaining nine games in succession in a dominant victory.

Garin was the only seed to lose in Brazil, however, as Lorenzo Sonego was on the right side of a 6-2 6-0 scoreline against 2019 winner Laslo Djere.

Fabio Fognini also advanced in straight sets, while Spanish pair Albert Ramos-Vinolas and Fernando Verdasco similarly eased through.

At the Delray Beach Open, 2021 runner-up Sebastian Korda defeated Thanasi Kokkinakis in his first match since winning the Australian Open doubles title with Nick Kyrgios.

Former champion Sam Querrey came up short against Denis Istomin.

Sebastian Baez stunned world number 18 Cristian Garin in three sets to reach the last eight at the Cordoba Open, his first career ATP Tour quarter-final.

Baez took a set off Stefanos Tsitsipas – his first ever top-10 opponent – before losing at the Australian Open, but he has kicked on again in Argentina.

The 21-year-old faced a huge uphill battle when he fell a set behind to third seed Garin, who won in Cordoba in 2020.

However, Baez roared back in quite remarkable fashion to prevail 4-6 6-1 6-1 in perhaps the best result of his career – and one of his opponent's worst.

"It was a pretty bad match, one of the worst of my career in terms of feeling," Garin said. "He deserves it as well, but I feel like I wasn't up to it.

"I had a regular first set and then I couldn't find myself. The little adaptation I had was clear, I was slow. It was one of my worst matches in many years."

Baez faces Alejandro Tabilo next after his last-16 defeat of Carlos Taberner, but a tricky field remains as the two seeds in action besides Garin on Thursday both won.

The reward for Lorenzo Sonego and Albert Ramos-Vinolas is a match against one another on Friday.

Novak Djokovic cruised into the quarter-finals of Wimbledon with a routine straight-sets win over Cristian Garin.

Djokovic is bidding to tie Roger Federer and Rafael Nadal with a record 20th grand slam championship by defending his 2019 title.

Since losing the opening set of the tournament to Jack Draper, Djokovic has been imperious form and he eased past Garin on Centre Court on Monday.

This was not vintage Djokovic, but his consistency on serve, strength on the return and remarkable movement skills helped him secure a 6-2 6-4 6-2 triumph to set up a last-eight meeting with Andrey Rublev or Marton Fucsovics.

Djokovic raced into a commanding position in the first set, winning the opening eight points of the match.

Indeed, Garin, aiming to reach the quarter-finals of a grand slam for the first time, appeared overmatched, winning only 10 points on serve as Djokovic took the first set with ease.

But the Chilean warmed to the occasion and displayed his resilience by saving three break points to hold for a 4-3 lead in a game that lasted over 10 minutes.

Garin's resistance was broken in his next service game through some deft Djokovic touch at the net and, after serving out the second, he broke in style in the first game of the third and raced through to a 50th grand slam quarter-final.

Data Slam: First serve fires Djokovic to half-century

Djokovic faced two break points in a one-sided contest, with Garin rarely able to threaten his first serve.

Indeed, Garin won 13 points on return and only three of those came against the Serbian's first serve in a performance he will surely want to forget.

By contrast, Djokovic won 48 per cent of points on Garin's serve and, save for the second set, rarely had to expend much energy in bringing up his half-century.

WINNERS/UNFORCED ERRORS

Djokovic – 28/23
Garin – 14/26

ACES/DOUBLE FAULTS

Djokovic – 9/1
Garin – 2/5

BREAK POINTS WON

Djokovic – 5/12
Garin – 0/2

Rafael Nadal saw off Alexei Popyrin to reach the Madrid Open quarter-finals on a day that saw Daniil Medvedev and Stefanos Tsitsipas suffer surprise defeats.

World number two Nadal, chasing a record-extending sixth title on home soil, advanced 6-3 6-3 in a time of one hour and two minutes on Thursday.

Popyrin, playing in his first last-16 match at a Masters 1000 event, broke Nadal in the sixth game of the opening set but the Spaniard otherwise looked comfortable.

Nadal converted four of his six break points to advance through to the last eight for a 15th time, where Alexander Zverev awaits.

"It was difficult," Nadal said in his on-court interview. "The court today was slippery, it was very fast, very dry conditions. The ball was flying a lot. The beginning was super tough. 

"He was hitting every ball and hitting the spots. I'm happy with the victory. It was an important victory, he came here playing well. Every match is tough."

Zverev, who won the competition in 2018, beat British number one Dan Evans 6-3 7-6 (7-3) to set up a meeting with Nadal

However, second and fourth seeds Medvedev and Tsitsipas saw their participation come to an end at the hands of Cristian Garin and Casper Ruud respectively.

Medvedev, who is still yet to reach the quarters in Madrid, lost the only break of serve in the third game of the opening set but recovered by taking the second set in a tie-break.

Garin dominated the deciding set, the world number 25 breaking Medvedev twice and, after a short delay to fix a broken net, advanced 6-4 6-7 (7-2) 6-1.

Tsitsipas, who held championship point against Nadal in the Barcelona Open final, failed to break Ruud on a single occasion as he fell 7-6 (7-4) 6-4.

Alexander Bublik is next up for Ruud after beating Aslan Karatsev 6-4 6-3, while Matteo Berrettini - 7-6 (7-4) 6-4 winner against Federico Delbonis - will meet Garin.

Also vying for a place in the semi-finals are John Isner and Dominic Thiem, who are set to face off after beating sixth seed Andrey Rublev and Alex de Minaur respectively.