LONDON — Chelsea finally seems to have found the solution to its striking struggles. Diego Costa took his goal haul to seven in four matches with a hat trick against Swansea on Saturday while Loic Remy also scored on his debut.
The 4-2 victory was Chelsea's fourth win in four matches this season and ended Swansea's perfect start to the Premier League season. Costa, who joined from Atletico Madrid for more than $50 million in July, is the first Chelsea player in 86 years to score in his first four games.
Just how much a team relies on a lethal striker is clear at Liverpool, which was beaten 1-0 by Aston Villa. Gabriel Agbonlahor's ninth-minute goal inflicted Liverpool's second loss in four games since last season's runners-up sold Luis Suarez to Barcelona.
In London, there was no debut goal for Arsenal striker Danny Welbeck in a 2-2 draw with champion Manchester City.
Like Arsenal, north London rival Tottenham also conceded late to draw 2-2 at Sunderland as Harry Kane scored an own goal.
It took until just before half time for Costa to equalize for Chelsea, and there was no stopping the Brazil-born Spain forward after his header from Fabregas' corner.
The pair combined 11 minutes into the second half with Costa finishing clinically from a cutback by Fabregas who now has six assists in his four games since leaving Barcelona.
Costa completed his hat trick in the 67th after Ramires scuffed a shot into his path.
"He's comfortable in the team," Mourinho said. "The team was built in a way where we were waiting for a certain type of striker. I think now everybody knows Chelsea did the right thing waiting for him."
Costa's work was done but his replacement, Remy, didn't take long to make his mark. The French forward, signed from Queens Park Rangers after misfiring Fernando Torres was offloaded on loan to AC Milan, netted from Oscar's pass in the 81st. The goal ensured there would be no nervy finish after Jonjo Shelvey's goal for Swansea five minutes later.
"We have difficult weeks ahead of us," Mourinho cautioned, already eyeing Wednesday's Champions League opener against Schalke.
Liverpool returns to European football's elite competition after a four-year absence on Tuesday, hosting Bulgarian newcomer Ludogorets. Both Arsenal and Manchester City prepared for their Champions League matches in midweek with a pulsating draw.
Sergio Augero exploited gaps in the Arsenal defense to meet Jesus Navas' cross and put City ahead in the 28th. But Jack Wilshere inspired Arsenal's recovery in the second half, chipping the ball over goalkeeper Joe Hart and then heading to Alexis Sanchez to volley into the net.
But City leveled thanks to the hosts' poor defending in the 83rd when Martin Demichelis became the fourth player this season to score against Arsenal with a header.
"It was a game of top quality between two very good teams played at a tremendous pace," Arsenal manager Arsene Wenger said.
Southampton claimed the biggest victory of the day, a 4-0 rout of Newcastle that makes manager Alan Pardew's future look increasingly precarious. But Everton manager Roberto Martinez will be relieved after winning its first match of the season. Romelu Lukaku and Steven Naismith scored in the 2-0 victory over West Bromwich Albion.
Leonardo Ulloa gave Leicester a 1-0 victory at Stoke for its first triumph in the topflight since gaining promotion, but fellow newcomer Burnley remains winless after Scott Arfield missed a penalty in a 0-0 draw at Crystal Palace in south London.