LONDON (AP) -- The grueling Thursday-to-Sunday turnaround that comes with playing in the Europa League might already be taking its toll on Chelsea.
By drawing 0-0 at West Ham, Chelsea dropped its first points in the Premier League and failed to score under Maurizio Sarri for the first time this season.
That Chelsea produced such a flat and insipid display at the London Stadium was perhaps no surprise, given six of the starting lineup against West Ham also began the Europa League match against PAOK Salonika in Greece on Thursday
And it probably didn't help that the Chelsea squad only returned from Greece on Friday afternoon after its flight back to London -- scheduled for late Thursday -- was canceled because of bad weather.
Sarri had already voiced his unhappiness that English clubs playing in Europe's second-tier competition aren't given dispensation to play their next Premier League game the following Monday.
"In Italy, it's possible," said Sarri, who arrived in the offseason from Italian side Napoli. "Here I have to play 64 hours after a Europa League match."
As it was, Chelsea had the early kickoff on Sunday and was neutralized by a West Ham defense that had conceded 11 goals in its first five games. Even Eden Hazard, who didn't travel to Greece in midweek, struggled.
"We need to move the ball quicker," Sarri said, "and we need more movement without the ball."
West Ham squandered the best chance of the game when Andriy Yarmolenko headed wide late in the second half from point-blank range.
The result left Liverpool as the only team with a maximum of 18 points from the first six rounds. Liverpool travels to Chelsea next weekend for the biggest game of the season so far.
NO ARSENAL HANGOVER
There was no such Europa League hangover for Arsenal, which beat Everton 2-0 for a fifth straight win in all competitions.
Alexandre Lacazette and Pierre-Emerick Aubameyang scored goals within three minutes of each other early in the second half at Emirates Stadium.
Aubameyang is having to play on the left wing to accommodate Lacazette as the team's central striker, but it is not stopping the Gabon striker from scoring. Since his Premier League debut on Feb. 3, only Liverpool's Mohamed Salah (16) has scored more goals than Aubameyang's 12.
Arsenal didn't have to travel for its Europa League match and had mostly fielded a reserve team in its 4-2 win over Ukrainian side Vorskla Poltava on Thursday. Aubameyang scored twice in that game, to go with a goal against Cardiff two league games ago.
While Arsenal manager Unai Emery's methods are starting to kick in, Everton is surprisingly laboring under its new coach, Marco Silva. Everton has won only one of its six league games, losing the last two.