Marcos Alonso, Eden Hazard and Cesc Fabregas were all on target as Chelsea defeated Arsenal 3-1 at Stamford Bridge to move 12 points clear at the top of the Premier League table.
Giroud scored a consolation goal for Arsenal deep into stoppage time, heading in a Nacho Monreal cross, but it was too little, too late for the visitors.
Hull City inflicted a fourth defeat in five games in all competitions on Liverpool with a 2-0 win at the KCOM Stadium to boost their fight against relegation.
Hull scored through Alfred N’Diaye and Oumar Niasse.
Sam Allardyce’s reunion with Sunderland was an unhappy one as his former club recorded a 4-0 win against Crystal Palace at Selhurst Park.
Sunderland scorers were Lamine Kone, Didier Ndong and Jermain Defoe with a brace.
Romelu Lukaku scored four goals and registered an assist as Everton saw off Bournemouth with a 6-3 win at Goodison Park.
James McCarthy and Ross Barkley were other scorers for Everton while Bournemouth replied with two goals from Joshua King and another from Harry Arter.
West Ham came from behind to record a 3-1 win against Southampton at St Mary’s and move into the top half of the table.
Saints took the lead to debutant Manolo Gabbiadini before the Hammers returned fire with goals from Andy Carroll, Pedro Obiang and an own goal by Saints’ Steven Davis.
Burnley’s away troubles continued as they went down to a 2-1 defeat to Watford at Vicarage Road.
Troy Deeney and M’Baye Niang scored for Watford while Burnley replied with a penalty by Ashley Barnes.
James Morrison scored the only goal of the game as West Bromwich Albion saw off Stoke City with a 1-0 win at The Hawthorns.