Sergio Oliveira scored twice as 10-man Porto dumped Juventus out of the Champions League with a scintillating away goals victory after a 3-2 second-leg defeat in Turin.

Juventus' task of overturning a 2-1 deficit from the first leg was compounded when Oliveira's penalty gave Porto a the lead after 19 minutes, but Federico Chiesa netted twice in 14 second-half minutes - either side of a red card shown to Porto striker Mehdi Taremi - to take the round-of-16 tie into extra-time.

Oliveira buried a stunning second goal of the night with five minutes left in the second period of extra-time, only for Adrien Rabiot to equalise and set up a tense finish.

Porto held on to spark wild celebrations on the visiting bench as Juve's quest for a first European title since 1996 ended in failure, heaping pressure on head coach Andrea Pirlo.

Juventus have announced midfielder Rodrigo Bentancur has tested positive for COVID-19.

The Uruguay international – who played the entire match as Juve defeated Spezia 3-0 in Serie A action on Tuesday – is asymptomatic, as confirmed by the club on Thursday.

Bentancur is now isolating and seemingly certain to miss Saturday's league game against Lazio in Turin.

"The club is in contact with the relevant health authorities for the definition of an effective implementation of the protocols required to allow the training and competition activities of the team group," Juventus said in a statement.

The 23-year-old's positive test also makes him a major doubt for the upcoming return leg of the last-16 Champions League tie against Porto.

Juve lost 2-1 in the first meeting, with the reverse fixture to take place next Tuesday.

Bentancur has made 33 appearances in all competitions this season, including 18 starts in the league for Andrea Pirlo's side.

Giorgio Chiellini will be monitored on a daily basis after scans revealed the Juventus defender suffered no muscle damage to his right calf against Porto. 

Chiellini was forced off in the first half of Juve's 2-1 Champions League defeat away in Portugal on Wednesday, Merih Demiral taking his place in the 35th minute. 

The Serie A side were already one goal down at that stage, while Moussa Marega added a second for Porto soon after the break. However, Federico Chiesa halved the deficit with a potentially crucial late away goal in the first leg of the last-16 tie. 

Porto will travel to Turin for the return fixture on March 9 and, having avoided any serious injury, Chiellini could be fit to feature on home soil. 

"Giorgio Chiellini underwent radiological examinations this morning at the J | Medical that excluded muscle injuries to his right calf. His condition will be monitored day by day," a statement from the club read. 

Andrea Pirlo's squad underwent a recovery session on Thursday as they turn their focus back to league matters. 

The reigning champions are next in Serie A action on Monday, when they host bottom club Crotone at the Allianz Stadium. 

Chiellini – who has helped the Bianconeri win nine straight top-flight titles in Italy – has made 15 appearances in all competitions this season, Pirlo's first in charge.

Cristiano Ronaldo is "selfish" and is struggling to adjust to Andrea Pirlo's style of play at Juventus, according to former Italy international Antonio Cassano.

Juventus suffered a surprise 2-1 loss away at Porto in the first leg of their Champions League last-16 tie on Wednesday, with Federico Chiesa scoring in the 82nd minute after Mehdi Taremi and Moussa Marega put Sergio Conceicao's side in control.

Ronaldo supplied two key passes and only had one shot on target in the match, with the Bianconeri facing possible elimination in the first knockout round for the second straight season. It was the first time Ronaldo had registered one shot or fewer in a Champions League match since November 2019 against Atletico Madrid.

Juve spent €112million to bring five-time Champions League winner Ronaldo to Turin in 2018 with the aim of boosting their chances of lifting the trophy for the first time since 1996.

Cassano thinks Ronaldo has struggled to adapt to the philosophy of rookie head coach Pirlo and is too focused on himself to help the team.

"I have always said, even though he is a phenomenon and has scored a billion goals, that with Andrea Pirlo's idea of football he could run into difficulties," Cassano said on Christian Vieri's Twitch channel BoboTV.

"He scores a goal per game, it's true, but he struggles with Andrea's idea. He's always been a bit selfish, he doesn't give a damn about others scoring goals.

"He's the kind of player that lives to score, not for the game, for the great match. He lives to score and in this moment the situation is getting worse. The years pass for everyone and he is having difficulties.

"The paradox is that Juventus have bought a player who has won five Champions Leagues but has so many difficulties in the Champions League.

"This is because, since Sarri, Juventus are trying to show a style that is different to its history. It's clear that Pirlo must be judged in four or five years, but Juventus want everything immediately."

Ronaldo has scored 88 goals in 116 games in all competitions for Juve and has supplied 19 assists. Juan Cuadrado (21) is the only Juventus player to have laid on more goals since the Portugal captain's arrival ahead of the 2018-19 season.

Andrea Pirlo felt a nightmare start left Juventus "a little bit scared" but Federico Chiesa's away goal at Porto got them "back on track" in the Champions League last-16 tie. 

Porto will travel to Turin for the second leg with a 2-1 lead after catching the Serie A champions cold twice at Estadio do Dragao on Wednesday. 

Rodrigo Bentancur gifted Mehdi Taremi a Champions League goal with a terrible pass to goalkeeper Wojciech Szczesny after just over a minute, while Moussa Marega doubled Porto's advantage just after the break. 

Juve rarely posed a threat in a flat display before Chiesa gave them hope when he struck eight minutes from time, with Cristiano Ronaldo denied a penalty right at the death in a miserable return to his homeland. 

Pirlo thought Juve, who lost captain Giorgio Chiellini to a calf injury in the first half, struggled to recover after such an early setback in proceedings. 

"The approach became wrong after the first minute. When you have conceded a goal like this it is normal to be a little scared, you lack the certainties that should never be lacking [at this stage of the competition]," the former Italy international told Sky Sport Italia. 

"The boys are a little down, we conceded a strange goal, then the match they wanted to play was set up and it became much more difficult." 

Pirlo added: "The tiredness after so many challenging matches is there, it is not easy to keep the same pace, but it shouldn't have happened. Fortunately, we got back on track, now we will focus on the return [leg]."

Alvaro Morata has been struggling with illness and although he came on midway through the second half, Pirlo revealed the striker still felt unwell after the game. 

He said: "Morata was not well, he has not been at his best for a few days. He came on when he needed to, but after the game he felt faint, he was a bit on the edge." 

Danilo will be suspended for the second leg next month after the full-back was shown a yellow card.

Mehdi Taremi scored after only 61 seconds as Porto caught lacklustre Juventus cold twice to seize the initiative with a 2-1 first-leg win in the Champions League round of 16.

Porto had never beaten Juve in five European matches, but the Primeira Liga champions made it a miserable return to his homeland for Cristiano Ronaldo on Wednesday.

Ronaldo was starved of service as Sergio Conceicao's side showed a far bigger appetite for the fight at Estadio do Dragao, with Taremi gifted a first Champions League goal by a terrible mistake from Rodrigo Bentancur.

Moussa Marega doubled Porto's lead right at the start of the second half, but Federico Chiesa struck eight minutes from time to leave the tie well poised ahead of the second leg on March 9.

Bentancur made it a nightmare start for Juve, failing to get enough on his back pass and allowing Taremi to slide in ahead of Wojciech Szczesny for his fourth goal in as many games.

That early blow failed to jolt Juve into life and Matthijs de Ligt deflected Sergio Oliveira's shot wide after a sloppy pass from a shaky Szczesny.

The Bianconeri lost captain Giorgio Chiellini, who was replaced by Merih Demiral, to a calf injury before Agustin Marchesin was finally called into action, diving to his left to keep out Adrien Rabiot's acrobatic attempt.

Juve were caught napping again at the start of the second half, when Marega's left-footed strike beat Szczesny at his near post after Wilson Manafa cut the ball back at the end of a marauding run.

The impressive Oliveira came close to adding a third Porto goal when his strike was saved by Szczesny, while Bentancur rifled just over the crossbar at the other end in a rare moment of concern for Conceicao's well-drilled side.

Porto looked rock solid but their run of five consecutive Champions League clean sheets ended when Chiesa converted Rabiot's cutback and Marchesin denied Alvaro Morata an equaliser soon after.

Ronaldo wanted a penalty for a challenge from Zaidu Sanusi but referee Carlos del Cerro Grande and the VAR saw it otherwise as Porto held on to their slender advantage.

Juventus forward Cristiano Ronaldo will look to inflict more Champions League pain on Porto and Borussia Dortmund travel to Sevilla for the first leg in the round of 16 on Wednesday.

Juve advanced from Group G at a canter, winning five of their six games to finish level on points with Barcelona.

The Serie A champions will be expected to knock Porto out, but Andrea Pirlo will be braced for a stern test in the first leg at Estadio do Dragao.

Sevilla do battle with Dortmund at Estadio Ramon Sanchez Pizjuan a couple of days after it was announced that Borussia Monchengladbach head coach Marco Rose will take over at the Bundesliga club at the end of the season.

We take a look at the best stats on the two ties courtesy of Opta.

Five-time Ballon d'Or winner Cristiano Ronaldo will play in his native Portugal for Juventus for the first time on Wednesday and coach Andrea Pirlo is expecting something special from his talisman.

Juventus meet Porto in the Champions League last 16 on Wednesday, with the Old Lady determined to improve upon last year's continental exit at this stage to Lyon.

Madeira-born Ronaldo, 36, has not played club football in Portugal since November 2016 when Real Madrid defeated his former club Sporting CP 2-1 in the Champions League.

Pirlo said Ronaldo's return home had provided added motivation for Portugal's all-time top scorer and current international captain.

"[Cristiano Ronaldo] is back home in Portugal," Pirlo said on Tuesday. "He is keen to score even more.

"He proved in the Coppa Italia and with his history in the Champions League, that he lives on the adrenaline of the knockout stages. He is proud to be back home and wants to show them who Cristiano Ronaldo still is."

Ronaldo netted a double in Juve's Coppa Italia semi-final victory over Inter earlier this month, while he is a five-time Champions League winner (four times with Real Madrid and once with Manchester United).

However, continental success has eluded Ronaldo since his move to Juventus in 2018, having lost in the 2018-19 quarters to Ajax and the 2019-20 last 16 to Lyon.

Remarkably since his move from Madrid to Turin, Ronaldo has scored all seven of Juventus' goals in the Champions League knockout stages, which was not lost on skipper Giorgio Chiellini.

"Cristiano is special, but I am not the one who discovered that," Chiellini said.

"He has been added value for us. We have been lucky to train with him to see every day the little secrets helping him become the true champion he is.

"Tomorrow we will play in Portugal, his home, I hope he will have even more motivation to perform well and score."

Cristiano Ronaldo says Juventus need to "bring their A game" as they begin their quest to reach a first Champions League final in four years.

The Serie A champions progressed as winners of Group G after a 3-0 win over Barcelona at Camp Nou on matchday six.

They begin the knockout phase on Wednesday against Porto, who were the only side to avoid two defeats against Manchester City in Group C.

Porto have failed to beat Juve in five previous European encounters and the Bianconeri are one of only two teams to play the Portuguese giants away at least twice without ever conceding a goal.

Andrea Pirlo's side have won 11 of their previous 13 Champions League matches, including all three away from home this season, but they come into the contest off the back of a 1-0 league loss to Napoli that leaves them eight points behind leaders Inter, who have played a game more.

Juve have failed to get beyond the quarter-final stage since they last reached the final in 2016-17, when two goals from Ronaldo helped Real Madrid to a 4-1 win in Cardiff.

The 36-year-old is determined to lead Juve back to another final this term as they aim to end a 25-year wait for European football's biggest club prize.

"This is what Champions League is all about: the knockout rounds," Ronaldo wrote on Instagram on Tuesday. "It's almost as if another competition starts from this point on and everybody has to bring their A game, because every detail can make the difference.

"In the last couple of years we went home sooner than we wanted, but we continue to aim higher every season and this year is no exception.

"Tomorrow we have a very importante [sic] game against a very strong team and I can only hope that it may be the beggining [sic] of the long walk we want to take until the final. Respect for the opponent, ambition for the victory and 100 per cent focus on our goals. Let's go, guys! Fino Alla Fine!"

Porto were the first team Ronaldo faced in the Champions League knockouts in the 2003-04 campaign, when Jose Mourinho's eventual winners eliminated Manchester United in the last 16.

His last appearance against them came five years later, when his Puskas Award-winning goal at Estadio do Dragao sent United through to the semi-finals.

Juventus will be without Leonardo Bonucci for Wednesday's Champions League last-16 match at Porto.

Centre-back Bonucci sustained a minor muscular problem during training and joins Juan Cuadrado (hamstring) and Paulo Dybala (knee) on the sidelines.

However, Juve head coach Andrea Pirlo is boosted by the return of Aaron Ramsey from a muscular complaint of his own - the Wales midfielder having been absent from the Serie A champions' four games so far across all competitions this month.

"Leo is not available, he had a little problem in training. We will evaluate but he is not available for tomorrow," Pirlo explained at his pre-match news conference.

"Ramsey can play while Dybala is not ready yet, but everyone wants to be with the team."

Porto followed their opening 3-1 defeat to Group C winners Manchester City with five consecutive clean sheets in this season's competition.

Pirlo knows Sergio Conceicao's men will prove a tough nut to crack and likened them to Diego Simeone's famously robust Atletico Madrid.

"I expect a very complicated match, they defend very well," he said.

"They are a team with a bit of the Atletico Madrid style: tight, compact lines.

"We must not force plays. The Champions League is a particular competition, different from the [Italian] championship.

"There are many teams fighting to win, everyone wants to do it and it depends a lot on [your form] when you face the teams. It is important to be mentally ready."

A 1-0 weekend defeat at Napoli due to Lorenzo Insigne's first-half penalty left Juve fourth in Serie A - eight points shy of leaders Inter, albeit with a game in hand.

It means the Bianconeri could relinquish possession of the Scudetto for the first time in a decade, but Pirlo insists his maiden season at the helm remains broadly on track.

"We won the Supercoppa Italiana, we are in the final of the Coppa Italia, we are in the running for the Champions League," he said.

"We are still well placed in the league. We are in the running on all goals and this is the most important thing."

Ending Juve's 25-year wait for a third success in Europe's premier competition would certainly represent a job well done. 

"The Champions League is a goal," Pirlo added. "The important thing is to believe in it, to know that we are a team that can reach the end. 

"This is the most important thing."