Liverpool crashed to a shock 3-0 defeat at West Brom in Brendan Rodgers' first Premier League match as Reds boss, while Arsenal started life without Robin van Persie with a dour 0-0 draw against Sunderland on Saturday.
Rodgers took over from Kenny Dalglish after Liverpool finished eighth last season, their worst final position for 18 years, and on the evidence of a shocking result at the Hawthorns the former Swansea manager still has plenty of work to do.
Giving debuts to new signings Joe Allen and Fabio Borini, Rodgers might have feared the worst when Zoltan Gera blast Albion into the lead with a stunning 43rd-minute strike.
Pepe Reina kept Liverpool in the match when he saved Shane Long's woeful second half penalty after Reds defender Daniel Agger was sent off for a professional foul.
But Albion won another penalty in the 64th minute and this time Nigerian striker Peter Odemwingie stepped up to blast home.
And Romelu Lukaku, on loan from Chelsea, rubbed salt into Liverpool's wounds when he marked his West Brom debut with a 77th-minute strike.
"Some decisions went against us. The sending off and penalties were very, very harsh I felt," Rodgers said.
"We will have more days like this along the way, that is the reality, but I could not ask any more from the players."
Arsenal manager Arsene Wenger saw his Gunners team fail to break down Sunderland at the Emirates Stadium in the first game since Dutch striker van Persie's move to Manchester United.
Wenger gave debuts to Germany striker Lukas Podolski and Spain midfielder Santi Cazorla, while French forward Olivier Giroud, another new signing, came off the bench.
But the new boys were underwhelming, with Giroud missing the best chance of the afternoon.
"Playing three strikers didn't work. We had no space, and the passing was not quick enough so it was difficult for them," Wenger said.
"But it's one game and it's too early to draw definitive conclusions."
New Tottenham manager Andre Villas-Boas suffered a losing start as Newcastle won 2-1 at St James' Park in the day's late game.
Villas-Boas, sacked by Chelsea last season, saw Newcastle take the lead through Demba Ba's superb 54th-minute goal.
Jermain Defoe equalised with a close-range effort in the 76th minute, but Hatem Ben Arfa was hauled down by Aaron Lennon four minutes later and the French midfielder picked himself up to score the spot-kick.
West Ham enjoyed a winning return to the top flight as Sam Allardyce's side beat Aston Villa 1-0 at Upton Park in Paul Lambert's first game as Villa boss.
The Hammers, promoted via the Championship play-offs, took the points when Kevin Nolan sidefooted home in the 40th minute.
Swansea manager Michael Laudrup savoured a five-star debut as new boy Michu inspired a 5-0 demolition of QPR at Loftus Road.
The Spaniard scored twice before a Nathan Dyer double and Scott Sinclair's late strike completed the rout.
Australian goalkeeper Adam Federici's first-half howler gave Stoke the lead against Reading but Adam Le Fondre's late penalty earned a 1-1 draw and a point for Premier League newcomers.
At Craven Cottage, Fulham striker Mladen Petric showed there is life without Clint Dempsey as his debut double clinched a 5-0 win over Norwich.
Damien Duff set the ball rolling with the first goal in the 26th minute before Petric scored twice and set up another for Alex Kacaniklic with Steve Sidwell's 87th minute penalty completing the Cottagers' big win.