City, which racked up 98 points to beat Liverpool by a point last season, rarely looked like getting out of second gear with a measured performance at London's Olympic Stadium. "At times we were a bit sloppy in the first half, but once the second goal went in I thought the boys were brilliant," Sterling told BT Sport 1. "It was quite difficult first half to get the cobwebs off, but once we got our rhythm the chances came."
Riyad Mahrez, back in England after leading Algeria to the African Cup of Nations title, had the visitors' first effort in the ninth minute, and should have done better again after cutting inside Aaron Cresswell before shooting right of the post.
Jesus broke the deadlock in the 25th minute, converting Kyle Walker's cross from close range after Mahrez had played the England right-back in on the right. West Ham rarely looked convincing. City's Oleksandr Zinchenko intervened when Manuel Lanzini was through at the other end, before Ederson had little trouble gathering the ball from record signing Sebastien Haller's attempted overhead kick.
It was only a matter of when City, with summer signing Rodri looking assured in midfield, would increase the tempo and make more of its superiority. Kevin de Bruyne set up Sterling to score through Lukasz Fabianski's legs in the 51st, minutes before Jesus had a well-worked team effort ruled out through VAR for offside. Sterling, played in by David Silva before he crossed for Jesus' tap in, appeared to have his shoulder ahead of the defender.
Ederson was forced to make a double-save from Javier "Chicharito" Hernandez, then Lanzini in West Ham's best phase. "They had an incredible chance and it could go 1-2 with 15 minutes left. So you have to be strong, calm and positive. You have to control your emotions," said City coach Pep Guardiola.
VAR was needed again when Sterling grabbed his second in the 75th, timing his run for Mahrez's ball over the top before lifting it over Fabianski, but this time the goal was allowed. Then Aguero was given a second chance to take his penalty after Fabianski saved his first effort. A VAR check showed Declan Rice was encroaching in the penalty area.
Aguero made it 4-0 in the 86th and Sterling wrapped it up in injury time, becoming the first since Didier Drogba in 2010-11 to start with a hat trick on the league's opening weekend.
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