Manchester City came from two goals down to reach the FA Cup semi-finals, with Sergio Agüero heading a controversial winner two minutes from time. The Argentine striker appeared marginally offside when he met Bernardo Silva's cross, but in the absence of VAR, the goal stood to secure a 3-2 victory.
City's equaliser was also contentious, as referee Andre Marriner awarded a soft penalty for a foul on Raheem Sterling. Agüero's spot-kick hit the post and went in off Swansea goalkeeper Kristoffer Nordfeldt. Manager Pep Guardiola expressed regret over the decisions, saying: 'Why is VAR not here? It's a question for the authorities. If it is not a penalty, and it is offside like the people say, I'm sorry.'
Swansea had taken a deserved lead through Matt Grimes' penalty after Fabian Delph fouled Connor Roberts, before Bersant Celina curled home a stunning second. The Championship side dominated much of the game, with Daniel James causing constant problems for City's defence.
Guardiola introduced Agüero and Sterling just after the hour mark, and Bernardo Silva pulled one back in the 69th minute with a crisp first-time strike. Sterling missed a chance to level before winning the penalty that led to the equaliser. Agüero then headed the winner, sparking celebrations from the visitors.
The victory keeps City's hopes of an unprecedented quadruple alive. Guardiola said: 'When you fight for all the titles, you don't have rest and every three days there is a game. It is so, so healthy to win these kind of games.'
