By Sean Walsh Manchester City’s quest for a record fifth-straight Premier League title began with a 2-0 win at Chelsea on Sunday. The Blues’ first competitive match under Enzo Maresca ended in a loss, but there were still positives to take from this Stamford Bridge encounter. Erling Haaland and ex-Chelsea midfielder Mateo Kovacic landed the fatal blows as the champions came away with all three points. Here’s what we learned from Sunday’s match. 1. Maybe Chelsea aren’t hopeless after allBefore a ball had been kicked this season, Chelsea were written off, their hopes seemingly dashed more by the…