When he had played, he was below his imperious best, but Tuesday's sparkling display was a reminder of how good he is in full flow - and how important he is to his side's title defence.

City had gone top of the table at the start of December largely without his help - but he was inspirational as they demolished Marcelo Bielsa's side to move four points clear.

De Bruyne's reduced impact this season can be measured in the assists he has contributed - zero - a stark contrast between the 12 he managed in 2020-21 and the record-equalling 20 from the 2019-20 campaign.

He did not break his duck against Leeds but his strikes either side of half-time doubled his goals tally for the season and his all-round display was superb - he had nine shots, made four key passes and his distribution in midfield was as good as ever.

De Bruyne will hope it draws a line under a difficult season so far. He returned from the European Championship with an ankle injury and after starting on the bench at Tottenham on the opening day in August he did not feature for another month, then tested positive for Covid-19 in November.

"A lot has happened this year, a little bit out of my control," he told BT Sport. "The only thing I could do is work hard and come back as quick as possible. It's unfortunate with everything that has happened and at the time I was coming back I got Covid. It happened and now we are working hard to come back to a good level.

"I think we played incredibly well, especially against the way they pressed. We found the right times to attack them. When were were 3-0 or 4-0 up it gets tough for them and they tried to keep it tight in the second half, but we had a lot of chances to score more.

"It's good for everybody, a lot of people who maybe didn't play a lot played today and chipped in. For the whole team it is a booster."

There will be much tougher tests ahead as De Bruyne, 30, returns to peak fitness, with the champions facing Leicester, Arsenal and Chelsea among others over the next month.

But the midfielder's performance in City's second-largest top-flight victory was hugely encouraging for his manager.

"I am really pleased he is coming back step by step because he struggled at the beginning of the season a lot," said Guardiola. "He played important games not at his best level, he got a little bit of rhythm and tempo but then he got Covid. Hopefully now he can maintain this rhythm for longer because we need him, absolutely we need him.

"In the minutes he played against Wolves [on Saturday] there was a little bit of a lack of rhythm and messy play but that is normal, it is not easy to come back from the bench.

"He trained really well the last two days and this type of game where it is a little bit more open - they put a lot of players in front and a lot of players wide - and in transition, Kevin is the best.

"Sometimes he struggles a little bit when the other team settles so, so deep and so tight like, for example, Wolves but we are pleased because we need him.

"We are together six seasons, I know him very well and he knows me very well and what he has done for me is everything and he has been so important. He's phenomenal."