Sergio Aguero scored four goals as Premier League leaders Manchester City showed Riyad Mahrez what he is missing in a 5-1 thrashing of Leicester City .
Mahrez returned as a substitute for Leicester after more than a week in self-imposed exile following the collapse of a move to City, and he likely watched on in awe as Pep Guardiola's side ran riot.
Aguero scored all his goals in the second half at the Etihad Stadium, propelling City to a 16-point lead at the top of the table after Jamie Vardy cancelled out Raheem Sterling's early opener.
The first three City goals were all created by Kevin De Bruyne who, alongside Aguero, was also outstanding.
Mahrez was named on the bench after returning to training on Friday and he could only watch as City raced out of the blocks with Sterling opening the scoring inside three minutes.
The ever-impressive De Bruyne curled in a dangerous low ball behind the defence and Sterling tapped in at the back-post.
From there it seemed City would assert full control as they dominated possession but they struggled to create clear-cut chances.
Aguero threatened in the area but showed too much of the ball to Christian Fuchs and Leicester, having already warned City of their intention to counter, quickly broke upfield.
Nicolas Otamendi did win the ball back but then lost it again with a sloppy pass, and Vardy raced clear and beat Ederson with a clinical finish to pull Leicester level.
City needed to start applying the final touches and they did so early in the second period, ruthlessly exposing Foxes boss Claude Puel's decision to switch from a back three to back four.
De Bruyne was again at the heart of their good work, exchanging passes with Sterling and picking out Aguero at the far post for a simple tap-in after 48 minutes, and De Bruyne set up another for Aguero just five minutes later.
That put the hosts in firm command but Puel responded by sending on, to a mixed reception, Mahrez and, to a good hand, former City striker Kelechi Iheanacho.
But ot was to no avail and Aguero wrapped up victory with two more.
The Argentine completed his hat-trick - his third of the season - with a beautiful finish, clipping the ball over Kasper Schmeichel after a terrible error from the Leicester goalkeeper.
But Aguero saved the best until last, as he netted his fourth on 90 minutes with a thunderous strike - the cherry on what was a resounding win for City.