Ilkay Gundogan, Bernardo Silva and Sergio Aguero scored within nine minutes of each other in the last 16 first leg tie to almost certainly extend Basel’s wait for a first quarter-final appearance in the competition.
Gundogan curled in the fourth from the edge of the area in the 53rd minute as the runaway English Premier League leaders clocked up another emphatic win in their remarkable season.
Basel did their best to make a game of it and created several openings but looked vulnerable every time City attacked.
City, who have lost in three of their previous four appearances at this stage of the competition, enjoyed the lion’s share of the possession with 69 percent, although that was still unremarkable by their standards.
Despite the scoreline, City had 12 shots to Basel’s 11 and the Swiss could have taken an early lead.
Dimitri Oberlin got clear of City’s defence and tried to poke the ball past Ederson as the Brazilian rushed out of his area but got no power on the ball allowing Kyle Walker to clear easily.
Oberlin also had a penalty appeal turned down as he went over under a challenge from Nicolas Otamendi.
Reality struck for Basel in the 14th minute when Gundogan beat Fabian Frei to Kevin de Bruyne’s corner and headed in.
Four minutes later, Leo Lacroix failed to cut out Raheem Sterling’s cross and the unmarked Silva lobbed his shot over Tomas Vaclik’s attempted save, then Aguero scored the third from outside the area -- City’s fourth shot on target of the game.
Ederson made his first real save in the 49th minute, palming away Mohamed Elyounoussi’s long-range shot, but shortly afterwards, Aguero set up Gundogan who took one touch and placed a looping shot into the far corner.
A brilliant Vaclik save denied Gundogan a hat-trick late on but, even so, the second leg looks little more than a formality for Pep Guardiola’s side.