Sergio Aguero scored twice but a suspected knee injury for Aymeric Laporte cast a shadow over Manchester City's comfortable 4-0 home win over Mat Ryan's Brighton and Hove Albion.
Laporte's celebrations of a long-awaited France call-up this week appear likely to be short-lived after he was taken off on a stretcher in the first half.
The 25-year-old went down in discomfort following a collision with Adam Webster, an incident that is sure to give Pep Guardiola several sleepless nights over the international break.
City were leading courtesy of Kevin De Bruyne's second-minute opener and Aguero added two more either side of the interval before teeing up Bernardo Silva to add the icing 17 seconds after his introduction.
The champions started in the manner expected of them as David Silva darted in behind and delivered a perfect cut-back for De Bruyne to apply a simple finish.
Provider should have turned goalscorer on the half-hour mark but David Silva poked across the face after Raheem Sterling wriggled free in the box.
A subdued atmosphere gave way to concern when centre-back Laporte was forced off after attempting a challenge that earned him a booking.
But striker Aguero lifted the mood in the 42nd minute, cushioning De Bruyne's pass and emphatically capping a classy team move.
Fernandinho had replaced Laporte in City's defence and positioned himself well to nod away Leandro Trossard's scuffed, close-range finish shortly after the restart.
Aguero offered no such mercy, brilliantly curling beyond an outstretched Ryan to complete his brace in the 55th minute.
City moved back down the gears after wrapping up three points but there was time left for the two-goal Argentina star to add an assist to his impressive outing.
Aguero gathered Martin Montoya's poor header and spotted Bernardo Silva, who picked out the bottom-right corner to complete the scoring in the 79th minute.
What does it mean? Guardiola awaiting Laporte update
City's decision to not sign a replacement for captain Vincent Kompany may be about to backfire.
Laporte's injury leaves Nicolas Otamendi as the only fit senior centre-back on the club's books, with John Stones not fully recovered from a thigh problem.
Heading into the UEFA Champions League group stage with Fernandinho partnering Otamendi is not a scenario Guardiola will readily accept.
De Bruyne dominant in the middle
City's midfield trio of Rodri, David Silva and De Bruyne overpowered their counterparts and laid the platform for a straightforward victory.
The latter was especially effective, De Bruyne continuing his fine early season form with a tidy finish and smart assist for Aguero's first.
Trossard squanders Brighton's best opportunity
Belgian winger Trossard looks a good acquisition for Brighton but his inability to convert a gilt-edged chance after the resumption was always going to prove costly.
City's first assignment after the international break is a trip to Norwich City on September 15. Brighton entertain Burnley on the same day.