MANCHESTER, England (AP) — Manchester City’s sloppiest display of the Champions League brought plenty of reasons to be cheerful for Pep Guardiola.A 1-0 win over Feyenoord on Tuesday, sealed by Raheem Sterling’s 88th-minute goal, clinched top spot in Group F with a game to spare, meaning City can rest key players for its trip to Shakhtar Donetsk in the final matchday.That comes four days before what will be the most high-profile match of the English Premier League, a derby against Manchester United.City’s fifth straight victory in the group kept the team on course to become the first from England to complete the group stage with maximum points. That feat has been achieved by only six sides in the competition’s 25-year history.Then there was the sight of two teenagers, Phil Foden (17) and Brahim Diaz (18), making their Champions League debuts as late substitutes — much to the delight of City fans who have been waiting for the club’s much-touted academy to bring through players for the first team.This was not the same City that was knocking over allcomers in the Premier League, with 11 wins and 40 goals from 12 games, or that beat Napoli home and away to move…