Manchester City booked their place in the semi-finals of the FA Cup with a stunning 3-2 comeback victory against Swansea City but their reverse was marred by VAR (video assistant referee) controversy.

Sergio Aguero scored from the penalty spot for the Blues' second goal but replays appeared to show that Cameron Carter-Vickers' challenge on Raheem Sterling saw the Swansea defender make contact with the ball before felling the England forward.

Aguero netted City's third two minutes from time with a diving header but the Argentine's run to meet Bernardo Silva's cross appeared to originate from an offside position.

Swansea's players, who had defended their two-goal lead valiantly against the Premier League leaders, were left incensed by the key decisions and City's strikes would have been chalked off had VAR been in operation at the Liberty Stadium.

FA rules state that VAR must be used in the FA Cup - but only at games being held at Premier League stadiums.

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Swansea were in the Premier League between 2012 and 2018 and the Liberty Stadium is equipped for the use of VAR but FA officials decided against using the technology in order to maintain consistency in their ruling that only Premier League stadiums would use VAR.

Asked about the decisions, Guardiola said: "Honestly I didn't watch it. If it is not a penalty, i am sorry, If it is offside, I am sorry. Why is VAR not here? It's a question for the authorities.

"I don't like it but I honestly didn't watch the situations."