London - Manchester City opened the defence of their Premier League title in ominous fashion on Saturday as Raheem Sterling scored a hat-trick in a 5-0 thrashing of West Ham, while Burnley and Brighton enjoyed impressive wins.
However, the introduction of Video Assistant Referees (VAR) for the first time in the Premier League proved Saturday's big talking point with a series of reviews and delays at the London Stadium.
City had a goal ruled out for the tightest of offside calls against Sterling and Sergio Aguero was afforded the chance to retake a penalty by VAR after seeing his first attempt saved.
"Only what I wish is that VAR doesn't make mistakes please," said City boss Pep Guardiola, who felt that his side's disallowed goal should have stood.
Liverpool's 4-1 victory over Norwich on Friday sent the message to City that they are up for another titanic title battle after missing out by just one point last season.
But in a worrying sign for those trying to stop Guardiola's men romping to a third straight league crown, City cruised to victory despite being far from their best before half-time.
The visitors led at the break thanks to Gabriel Jesus' opener, but moved through the gears after the break as Sterling scored twice in 14 minutes.
Aguero then denied the England international the chance to seal his hat-trick from the spot, before the 24-year-old eventually grabbed his third goal of the game in stoppage time.
"Perfect start? It terms of the result yes, in terms of the performance no," said the ever-demanding Guardiola. "In the first-half we were sloppy with our passes."
POTTER'S PERFECT START
Brighton's new manager Graham Potter enjoyed a dream start to his time in charge as the Seagulls beat last season's FA Cup finalists Watford 3-0 at Vicarage Road.
Abdoulaye Doucoure's own goal gave the visitors a half-time lead before Florin Andone and Neil Maupay on his debut sealed a highly impressive three points for a Brighton side that narrowly escaped relegation last season.
Burnley were also 3-0 winners at Turf Moor as an Ashley Barnes double and Johann Gudmundsson's strike condemned Southampton to a heavy defeat.
Crystal Palace's wantaway star Wilfried Zaha put his grievances with the club's hierarchy behind him to make an appearance as a second-half substitute against Everton, but neither side could break the deadlock in a 0-0 draw.
Zaha could have lined up for the visitors at Selhurst Park as Palace ignored a transfer request from the Ivorian to reject two bids from the Toffees after interest from Arsenal earlier in the transfer window cooled.
Everton were one of the biggest spenders in the window with seven new signings, but were forced to hang on for a point when Morgan Schneiderlin was sent-off 14 minutes from time for a second yellow card.
Sheffield United grabbed a late point away to Bournemouth on their return to the top flight after a 13-year absence.
Chris Mepham put the Cherries in front just after the hour mark on the south coast, but Billy Sharp's strike two minutes from time salvaged a 1-1 draw for the Blades.
Last season's Champions League finalists Tottenham begin their campaign later on Saturday at home to Aston Villa.