Manchester City have edged into the EFL Cup quarter-finals on penalties, but only after Wolverhampton Wanderers had held the Premier League leaders to a goalless draw after 120 minutes at the Etihad Stadium.

Both clubs wasted opportunities in both normal and extra time, before City goalkeeper Claudio Bravo saved from both Alfred N'Diaye and Conor Coady to help the Premier League leaders to a 4-1 triumph from 12 yards.

It was harsh on a Wolves side who pulled off what had been considered an unimaginable achievement by keeping out City for 120 minutes of football, but Pep Guardiola will be delighted - and relieved - that his stars found a way past the stubborn Championship outfit.

It took all of six minutes for Aguero - who must wait to become the new all-time record goalscorer for City - to get a shot on goal but Wolves goalkeeper Will Norris was able to get a strong hand to the ball to turn away his 20-yard effort.

Before the quarter-hour mark, Aguero had two more opportunities, with a shot being diverted wide from a cross, and an attempt from closer to goal was sent high over the crossbar.

Wolves were offering very little in the final third, and constant City pressure led to their best opening of the game through Raheem Sterling, but the winger could only poke wide from close range after latching onto Ilkay Gundogan's pass.

However, after the half-hour mark, Wolves began to pose their own threat, with Ryan Bennett seeing a header saved by Bravo after rising above Danilo to meet Ben Marshall's cross.

Aguero got another shot on goal - this time firing too close to Norris from distance - but with two minutes of the first half remaining, Bright Enobakhare wasted a glorious opportunity for the visitors.

The youngster outmuscled Eliaquim Mangala before running clear on goal, but the 19-year-old's low shot was too close to Bravo, who stayed big to divert the ball behind for a corner.

City returned for the restart to play in the same manner in which they had approached the start of the game, but it took until the 57th minute for another chance to be created, with Bernardo Silva's close-range header being brilliantly kept out by Norris.

Either side of the hour mark, Wolves began to come back into the contest and Helder Costa was starting to have a bigger impact in the final third, with his run into the area being ended with a shot being pushed off target by Bravo.

It was not long before City were back on the offensive through Silva, who had all the time in the world to get a shot away from the right-hand side of the box before eventually being denied by Norris, while Danilo also got forward before seeing a rising shot tipped over by the goalkeeper.

As the game progressed the 90-minute mark, it was all City but both Danilo and Sterling wasted opportunities inside the 18-yard box, with Sterling failing to hit the target from a rebound.

However, in added-on time, Enobakhare should have won it for Wolves when running half of the length of the pitch but despite only having Bravo to beat from 12 yards, the Nigerian sent his effort straight at the goalkeeper.

It's an opening which eventually came back to haunt Wolves, and Guardiola was able to introduce Kevin De Bruyne, John Stones, Leroy Sane and Kyle Walker from the bench, with each player adding an extra level of class in various areas of the pitch to begin to nullify the threat being offered by the West Midlands team.

Unsurprisingly, the visitors were starting to wilt after a monumental effort to take City to extra time, but Wolves were able to get to half time in extra time, with Norris denying Sterling before Kortney Hause made an heroic block to prevent the winger from scoring from six yards out.

Soon after the restart, Yaya Toure was denied by a low save from Norris before the ball eventually found its way to Sane at the back post, but the German's half-volley was deflected inches wide of the top corner.

Both teams were out on their feet towards the end of extra time but Aguero did his utmost to win it for City in the final minute of added-on time, only to see his low strike go straight to Norris.

After the match went to penalties, Leo Bonatini opened the scoring for Wolves but it was City who made the most of the ABBA format with De Bruyne, Toure, Sane and Aguero all converting near perfect efforts from 12 yards to seal their team's place in the last eight.