LONDON - Juan Mata scored on his Chelsea debut to complete a 3-1 victory over Norwich on Saturday in a Premier League match overshadowed by teammate Didier Drogba being knocked unconscious.
Mata, who joined from Valencia earlier this week, netted in the 11th minute of stoppage time, which resulted from Drogba requiring treatment on the pitch after being accidentally punched by Norwich goalkeeper John Ruddy.
While the Ivory Coast striker was taken to hospital, Chelsea said he only had "mild concussion" and would be released on Saturday night.
"He is showing some good signs of recovery for us to be a little bit more tranquil," Chelsea manager Andre Villas-Boas said.
Frank Lampard restored Chelsea's lead from the penalty spot after Grant Holt cancelled out Jose Bosingwa's early opener.
Chelsea was kept off the top of the standings on goal difference by Liverpool, which beat Bolton 3-1 after goals from Jordan Henderson, Charlie Adam and Martin Skrtel.
Also Saturday, Franco Di Santo scored twice as Wigan beat Queens Park Rangers 2-0 and Mikel Arteta's penalty gave Everton a 1-0 win at Blackburn.
But there were scoreless draws between Aston Villa and Wolverhampton Wanderers, and Swansea and Sunderland.
Among Sunday's fixtures, Manchester United takes on Arsenal and Manchester City is at Tottenham.
At Stamford Bridge, Chelsea got off to the perfect start when Bosingwa scored his first goal since November 2008.
Just six minutes had elapsed when the Portugal defender found the back of the net from 25 metres (yards) via the inside of the post.
Norwich, though, was back in the game in the 63rd after Chelsea goalkeeper Hilario needlessly came racing off his line to claim a cross and collided with Branislav Ivanovic, allowing Holt to hook the ball into the empty net.
It got worse for the hosts as they tried to regain the lead, with Drogba knocked unconscious after an aerial challenge with Ruddy.
Doctors raced onto the pitch to treat the 33-year-old striker, with the game stopped for seven minutes while he was loaded onto a stretcher and carried off wearing a breathing aid.
The game turned back in the Blues' favour when a breakaway by Chelsea brought a penalty scored by Lampard.
At Anfield, Henderson and Adam scored their first goals since joining Liverpool in the off-season as Luis Suarez helped to overpower Bolton.
Henderson, who joined from Sunderland, struck in the 15th after Jussi Jaaskelainen parried a volley from Stewart Downing.
Former Blackpool midfielder Adam whipped in the corner that Martin Skrtel headed home in the 52nd.
And Adam got on the scoresheet a minute later when he finished off good work from Dirk Kuyt by firing low past Jaaskelainen.
Bolton pulled one back in stoppage time when Martin Petrov troubled Liverpool centre back Jamie Carragher and Ivan Klasnic nipped in to score.
The win gave Liverpool seven points after three matches — the same tally it took seven matches to hit last season when the Reds were initially battling against relegation.
At Ewood Park, Blackburn had two attempts to net from the spot and missed both.
Junior Hoilett saw his penalty saved by Tim Howard at the start of the second half before Mauro Formica shot against the post.
Arteta then showed Blackburn how it was done, clinching Everton's win with a penalty kick after Christopher Samba climbed on the back of Marouane Fellaini.
Everton celebrated its first win of the season while Blackburn is stranded on zero points after three games.
Swansea has two points but is yet to score since being promoted, drawing against a Sunderland side also searching for its first win.
Wigan is unbeaten and racked up three points for the first time this season after Di Santo scored either side of halftime against promoted Queens Park Rangers.
The former Chelsea forward fired a shot into the top corner and later saw a deflected strike loop over goalkeeper Paddy Kenny.
Like Wigan, Aston Villa and Wolverhampton Wanderers remain unbeaten after the local rivals drew.