LONDON — Manchester City, the Premier League champion, and Liverpool, who are strongly fancied to challenge them this season, put down markers with impressive wins in their opening games of the new campaign Sunday.

City won 2-0 away to Arsenal, which was sixth last season, and the country's highest spender Liverpool demolished West Ham United 4-0 at Anfield.

The champion, attempting to become the first team since Manchester United in 2009 to retain the title, was too good for an Arsenal side playing under new Spanish manager Unai Emery.

England's Raheem Sterling went past two weak challenges to put City ahead in the first quarter of an hour with his 50th league goal.

Soon after debutant Riyad Mahrez was substituted in the second half, having earlier forced Petr Cech into a good save, Bernardo Silva added the second goal in the 65th minute from an assist by Benjamin Mendy.

City has now lost only one away game in the league — at Liverpool — of its last 21, and manager Pep Guardiola was delighted with them.

"We made a good performance in general and day by day we will get better and better," he said.

Emery, meanwhile, will know he has much to do, even before a difficult local derby with Chelsea next weekend.

"In the first half we needed less respect for City and then more aggressive pressing," he said. "Second half we got better."

Earlier, Liverpool strolled to its usual victory over West Ham, whom it has now beaten 4-0, 4-1, 4-1 and 4-0 in the last four meetings.

Last season's Premier League top scorer Mo Salah was on target again, giving Juergen Klopp's side the lead after 19 minutes with a tap-in.

Poor defending cost the London side a second goal just before the interval, to Sadio Mane, who added a third after 53 minutes from an offside position.

Substitute Daniel Sturridge made it four just seconds after coming on near the end.

West Ham's new manager Manuel Pellegrini gave debuts to five of their 10 close-season signings but his revamped team rarely threatened Liverpool's expensive new Brazilian goalkeeper Alisson.

In contrast, midfielder Naby Keita, who cost Liverpool 50 million pounds ($63.84m) from RB Leipzig, was excellent throughout.

"We played as good as possible today and we extended a really good pre-season into the Premier League," Klopp said.

The result continued West Ham's dreadful record at Anfield, which now extends to one win in 46 league games. Liverpool has not conceded a goal in its last six home games in the league — since West Ham scored against them in February.

Sunday's other game was a goalless draw between Southampton and Europa League contestants Burnley.

New signing Joe Hart made some good saves for the visitors, as did Alex McCarthy in the home goal. — Reuters