Arsenal began the Premier League season with a shock 2-0 defeat by West Ham after a nightmare debut for new goalkeeper Petr Cech at Emirates Stadium on Sunday.

Cheikhou Kouyate headed West Ham into the lead just two minutes before the break after poor judgment by the former Chelsea 'keeper, who was then wrong-footed by Mauro Zarate's shot from outside the area in the 57th minute.

Tipped to be title challengers this season and coming off a 1-0 win over champion Chelsea in the Community Shield, Arsenal failed to create clear chances against a well-organized West Ham defense under new manager Slaven Bilic.

The London derby was briefly interrupted in the 75th after a nasty clash of heads in the area between Arsenal striker Olivier Giroud and West Ham defender James Tomkins. Both men were given immediate attention by team medical staff and both players saw the game out to the end.

Widely seen as one of the best moves of the pre-season transfer market so far, Cech's arrival for a reported fee of about 11 million pounds ($17.3 million) is designed to strengthen Arsenal bid for a first league title since 2004.

However, the 33-year-old goalkeeper was caught out just before the break when Dimitri Payet sent a free kick into the area. Cech decided to race off his line and try to clear the danger but Kouyate got to the ball first and sent a glancing header into an unguarded Arsenal net.

Superbly taken, the goal came against the run of play in a half where Arsenal enjoyed plenty of possession but lacked the decisive final ball.

And the same pattern continued after the re-start. Arsenal kept West Ham on the back foot, Giroud fired a half-chance into the side-netting and both Mesut Ozil and Aron Ramsey were kept busy trying to find a way through.

But instead of finding an equalizer, Arsenal fell further behind after Alex Oxlade-Chamberlain gave away possession as the home side tried to clear from the edge of its penalty area.

Zarate latched onto the ball, twisted and unleashed a low shot to Cech's right as the 'keeper prepared to cover the bigger gap to his left.

With an hour on the clock, West Ham had registered two goals from only two shots on target.

In a desperate bid to turn the game around, Arsene Wenger sent on Alexis Sanchez in the 67th minute, having planned to rest the Chile striker after his recent triumph in the Copa America.

Wenger sacrificed right back Mathieu Debuchy for Sanchez but the ploy failed to deliver, though Arsenal's sustained pressure led to the clash of heads as Giroud and Tomkins both jumped for an aerial ball.

After treatment, the game continued with Oxlade-Chamberlain firing a rasping shot into the side netting. Sanchez managed to get into a good position inside the area in the closing stages, but managed only a weak shot that summed up Arsenal's afternoon.

Southampton substitute Shane Long headed a late equalizer to earn a 2-2 draw at Newcastle on Sunday and deny Steve McClaren a winning Premier League start in charge of the home side.

Goals from Papiss Cisse and new signing Gini Wijnaldum put Newcastle in command after Graziano Pelle's 24th-minute opener for the visitors at St James' Park.

But Long, a 65th-minute replacement, rose to power home a cross from the Dusan Tadic with 11 minutes to go to secure a point.

It could have been even worse for McClaren, who watched Southampton striker Sadio Mane miss two glorious chances to win it in the closing seconds.

First Mane had a shot blocked by Jack Colback and then saw another effort drift just wide of the beaten Tim Krul's right-hand post.

Philippe Coutinho struck a superb late goal to give Liverpool a winning start to the new Premier League season with a barely-deserved 1-0 victory at Stoke on Sunday.

A drab encounter at the Britannia Stadium appeared to be drifting toward a goalless draw when the Brazilian midfielder suddenly found the net with a ferocious 25-meter shot in the 86th minute.

It was Liverpool's only serious effort of the game and, although the contest had opened up more in the second half, the home side seemed the more likely to score.

Along with a positive start to life without Raheem Sterling after his move to Manchester City, the victory also gave Liverpool a measure of revenge after being thrashed 6-1 at the same ground on the final day last season.

Rodgers is trying to build a new side after an extensive summer of recruitment and the departure of Sterling.