Playing their home games at the venue that hosted the 2012 Olympic Games has plenty of benefits for West Ham, but hosting City is not one of them. The referee called for VAR and found the goalkeeper was off his line before AGUERO took his shot.
Gabriel Jesus opened for the Sky Blues at the London Stadium.
Tanguy Ndombele makes his Premier League debut here and with the absence of Son Heung-min (suspended) Lucas Moura will be Spurs' biggest attacking threat alongside Harry Kane.
"It is going to change the dynamic not just for the team but for the spectators".
West Ham manager Manuel Pellegrini indicated that Man City used underhanded tactics to beat the Hammers. Sane joined Silva on three goals at London Stadium by full-time - a stunning piece of skill leaving Fabian Balbuena prone to make it 3-0.
Brighton made an excellent start under new boss Graham Potter with a surprise 3-0 win at Watford - thanks to an own goal from Abdoulaye Doucoure and second-half strikes by forwards Florin Andone and Neal Maupay.
A superb passing move cut the West Ham defence to shreds and Raheem Sterling was left with the simple task of picking his spot past Fabianski.
In a sure sign of things to come this season, the video assistant referee ruled a goal offside, another onside, awarded a penalty, and subsequently ordered its retake.
Things nearly got worse for the Hammers three minutes later when another clinical move saw Jesus tap in from close range.
Ederson was forced to make a double save from Javier "Chicharito" Hernandez, then Lanzini in West Ham's best phase.
However, the third did eventually arrive on 75 minutes after Sterling was played in before delicately looping the ball over West Ham goalkeeper Lukasz Fabianski - yet only after another check with VAR.
Sergio Aguero added to the woes of the Hammers with his strike from the penalty spot before the Algeria global provided the assist for Sterling to seal the victory.
The Argentine scored before Sterling completed his hat-trick in stoppage time - the first player to do so on the opening weekend of the Premier League since Didier Drogba in 2010.