* Chelsea beat Arsenal 3-1
* Alonso header put Chelsea ahead
* Hazard made it two with fine individual goal
* Fabregas lobbed Cech for late third
* Giroud scored Arsenal consolation in stoppage time
* Chelsea moved 12 points ahead of Arsenal at top of league
* Chelsea away to Burnley next, Arsenal host Hull City (Adds details, quotes)
Feb 4 (Reuters) - A firm header from Marcos Alonso, a dazzling individual effort from Eden Hazard and a lob from Cesc Fabregas earned Premier League leaders Chelsea an emphatic 3-1 victory over Arsenal on Saturday.
Chelsea moved 12 points clear of their London rivals and the chasing pack with a dominant performance at Stamford Bridge that featured one of the solo goals of the season from Hazard.
After Alonso had outmuscled Hector Bellerin to head home in the 13th minute, the Belgian struck early in second half, picking up the ball just past the halfway line and shrugging off Francis Coquelin before rounding Laurent Koscielny and dodging Shkodran Mustafi to score.
Chelsea outplayed Arsenal, watched helplessly by their suspended manager Arsene Wenger from the stands, and goalkeeper Petr Cech gifted Fabregas the third when he failed to clear and the Spaniard lofted the ball into an empty net.
Arsenal substitute Olivier Giroud headed a consolation goal in stoppage time but his side were left a dozen points adrift in third place, their title challenge once again all but over with three months of the season left.
Arsenal, who handed Antonio Conte's side their worst beating of the season in September, 3-0 at the Emirates, paid heavily for the temerity.
""We played a good game with a good intensity and organisation. We deserved to win today and I'm pleased for my players," Conte said.
"Fantastic. In football you get opportunities to put things right. I remember walking off after defeat at Arsenal, I felt like a bit of a mug after that game," Chelsea's Gary Cahill added. "That result added a bit of desire."
Arsene Wenger's men were the only side that Chelsea had not scored against this season but after a bright start for both teams with Alex Iwobi shooting just wide for the visitors and Cahill heading over, it did not take the Blues long to consign that statistic to history.
A terrific header from Diego Costa beat Petr Cech and looped up off the bar only for Alonso to overpower Bellerin to head home the rebound from close range.
Bellerin took a heavy fall on his back and had to be replaced by Gabriel, requiring a reshuffled Arsenal defence, and Chelsea began to take control.
Yet Arsenal came close a couple of times, Gabriel forcing a fine save from Thibaut Courtois with an unopposed header and Mesut Ozil producing a tame left-foot shot when well-positioned just before the break.
Arsenal's resistance, though, was broken in the most audacious way possible with Hazard producing a solo goal of rare splendour, featuring guts and strength as well as great skill.
The Belgian picked the ball up just inside his own half, swerved away from Koscielny and outmuscled Coquelin as he weaved towards the Arsenal goal.
By the time Koscielny got back into desperate defensive mode, the marauding Hazard again turned him inside out before directing the ball over Cech from close range for a wondrous score.
"It is always good to score beautiful goals, against a massive team. I enjoyed the game and the goals," Hazard told Sky Sports.
Arsenal came close with a header from Danny Welbeck, well saved by Courtois, but when Cech, an old hero at Stamford Bridge, played a loose ball out of a defence straight to Fabregas, the former Arsenal midfielder was merciless in his punishment, lobbing the ball expertly into an unguarded net.
Fabregas looked so embarrassed for his old club, out of respect he barely bothered to celebrate his first goal against Arsenal.
Giroud, too, could barely raise a smile when he headed home Nacho Monreal's cross as Arsenal pondered the death of another title challenge following a fourth defeat in their last nine league matches.
There is, though, no stopping Chelsea as they won their 14th of 15 home matches in all competitions this season, including the last 11 in a row. (Reporting by Clare Lovell and Ian Chadband, editing by Ed Osmond)