(CNN)The first score of the new Premiership campaign was neither one of flair or magical skill, instead it came courtesy of a gaff by Tottenham Hotspur defender Kyle Walker that resulted in an own goal.
Premier League: Own goal and red card mark opening day's marquee matchups
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The defensive error opened an active inaugural day to the 2015-2016 season, which included a shaky start by titleholders Chelsea.
With the sun shining over Old Trafford for an early kick-off, Manchester's new-look squad disposed of their London rivals in a match that began with high intensity, but leveled off after the Spurs' gift in the 22nd minute -- the result of Walker tracking back to cover an open Wayne Rooney.
Rooney's touch ricocheted off of Walker's foot to provide a rare moment of elation for the home crowd in the 1-0 victory. It was the first time in Premiership history that a season started on an own-goal.
"Today was all about the three points," said Rooney after the match, while contemplating how the new pieces of his team were fitting in. "We're still working on it, of course. It was a big victory today."
Spurs manager Mauricio Pochettino called the result "frustrating" and "disappointing."
"When you compete against a team like Manchester United, you need to avoid all mistakes," he said in post-match commentary on BT Sport. "One mistake, we give the opportunity to score. It's true that after we conceded the goal it was difficult to play the same way."
Last season's PFA young player of the year Harry Kane looked lively throughout, providing an excellent opportunity in the fourth minute with a skilful pass to Christian Eriksen, only for the Dane to float it over the crossbar.
Manchester United had a new look to them, with speedy winger Memphis Depay playing 67 minutes in his very first Premiership match. The 21-year-old was signed from PSV Eindhoven -- where he scored a goal in nearly half of his 90 appearances -- for $34 million in May.
"The first time you play in Old Trafford, it's always difficult," United manager Louis van Gaal said after the match. "I said to Memphis that he doesn't have to play with too much eager and too much passion."
Depay took over the attacking winger duties from Angel Di Maria, who was to sold to Paris Saint-Germain for a reported $68 million after one underwhelming season in Manchester. Fellow South American Radamel Falcao was sent to Chelsea on loan to nearly complete the pre-season makeover.
The Red Devils' biggest pre-match concern was their goalkeeper spot, with David de Gea rested by van Gaal in favor of Argentine Sergio Romero. The Spaniard has been linked with a move to Real Madrid and risking injury could have scuttled the transfer. De Gea's mind has also not been on the game, according to his manager.
"A goalkeeper is all concentration and focus," van Gaal said before the match. "He only gets four or five times that he has to save an attack, so it's all focus and concentration. We think that it is better for him (not to play)."
"For me it is not normal that he isn't playing, but in these circumstances it was the best decision and it was a very difficult decision," he added.
Former Spurs manager Harry Redknapp called the strategy "a massive, massive gamble," with the danger of Romero having a shaky start weighing against the risk of an unfocused de Gea, who was left off the team sheet entirely.
"We cannot let him go so easily," said van Gaal, citing de Gea as the best Manchester United player for the past two years.
United's most famous signing, German captain Bastian Schweinsteiger, didn't appear until the 59th minute when he filled in for Michael Carrick, but established his presence immediately. The 31-year-old, coming off a storied career at Bayern Munich, pointed to spots from the midfield like a police officer directing traffic.
The Premiers League's other marquee opening day matchup pitted defending champions Chelsea against eighth place finishers Swansea, in a game that caught fire from the start.
Brazilian Oscar showed off his free kicking abilities by sailing the ball around Lukasz Fabianski in the 22nd minute to give the Blues an early lead.
Andre Ayew scored in his debut with Swansea in the 28th minute, with the Ghanaian rocketing the ball past a diving John Terry. Only 90 seconds later Willian caught a lucky break off a deflection to put Chelsea back ahead.
But the action wasn't over in the first half. Chelsea goalkeeper Thibaut Courtois drew a red card in the 51st minute for his collision with Bafetimbi Gomis, who drove the penalty home to tie the match.
Despite a number of close chances playing against 10 men, Swansea failed to capitalize and allowed Chelsea to salvage a point in front of its home crowd in the 2-2 draw. Chelsea did not suffer a home loss in 19 Premiership matches last season.
In other action, Everton and Watford drew 2-2, newcomers Bournemouth lost at home to Aston Villa 1-0, Leicester beat Sunderland 4-2 while Crystal Palace beat Norwich away 3-1.