SHOWCASE-Soccer-Chelsea overpower Arsenal to stretch lead

* 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

CHELSEA 3 ARSENAL 1

Feb 4 ( Reuters) - A firm header from Marcos Alonso, a superb 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.

Alonso outmuscled Hector Bellerin to head home in the 13th minute and early in second half Hazard picked up the ball just past the halfway line and shrugged off Francis Coquelin before rounding Laurent Koscielny and dodging Shkodran Mustafi to score.

Chelsea outplayed Arsenal, watched 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 lifted the ball into an empty net.

Arsenal substitute Olivier Giroud headed a consolation goal in stoppage time. (Reporting by Clare Lovell, editing by Ed Osmond)