Sporting CP marked the final home game of coach Ruben Amorim's reign in stunning fashion as Viktor Gyokeres' hat-trick saw them come from behind to thrash Manchester City 4-1 and maintain their superb start to the Champions League on Tuesday.

The Portuguese league leaders were outplayed for most of the first half and should have trailed by more than Phil Foden's early goal, but Gyokeres levelled it up before the break.

City were caught cold at the start of the second period as Maximiliano Araujo finished a flowing move straight from the kickoff, before Gyokeres put Sporting further ahead minutes later from the penalty spot.

Erling Haaland had the chance to drag City back into the game but struck the crossbar with a penalty before Gyokeres wrapped it up for the hosts with another spot kick to send the Estadio Jose Alvalade crowd into raptures.

Amorim, who will take over as Manchester United manager on Nov. 11, leaves Sporting in a fantastic position in the Champions League group phase with 10 points from four games. City's first defeat leaves them on seven points.

"When you lost 4-1 you can't say too much," City manager Pep Guardiola said. "We made a fantastic first half but we struggled to score, we missed the simple passes.

"The second half we were emotionally not stable enough."

All eyes were on Amorim before kickoff after he accepted United's offer to take over from the sacked Erik Ten Hag.

The highly-rated 39-year-old has landed two Portuguese titles in four years with Sporting and they have started this season's domestic championship with 10 wins from 10 games.

Up against City's master tactician Guardiola, however, he was given an uncomfortable taste of what he can expect in the Premier League during a first half in which his side could have been blown away by an injury-hit City side.

Foden struck after four minutes when Sporting lost the ball inside their own half and the England forward advanced to smash his shot past Franco Israel.

Haaland, who had an off night, had several chances and Bernardo Silva also went close for City, while Gyokeres made a hash of a gilt-edged opportunity shortly after Foden's opener.

But Gyokores made no mistake when he was played through in the 38th minute by Geovany Quenda, dinking his shot in.

City never got going in the second half and were sloppy at the back as they went on to concede four goals in the Champions League for the first time since 2016.

Araujo was played in by Pedro Gonçalves to score in style then Josko Gvardiol shoved over Francisco Trincão in the area for Gyokeres to beat Éderson from the spot.

Gyokores completed City's misery with his hat-trick-sealing penalty, awarded for a foul by Matheus Nunes on Geny Catamo, to put Sporting second in the table.