Olivier Giroud scored his first goals of the season as Arsenal beat Sunderland 4-1 on Saturday, leaving the beleaguered northeast team with only two points after 10 Premier League games.

The France forward struck twice within five minutes of being introduced as a 69th-minute substitute to kill off hopes of Sunderland's fightback after Jermain Defoe's penalty had canceled out Alexis Sanchez's first-half opener for Arsenal.

The Gunners have now gone 14 games unbeaten in all competitions since the opening day of the season.

Sunderland lacked both the defensive resilience and the raw pace to compete, further weakening David Moyes' hold on the Sunderland job.

Mesut Ozil had already shot tamely at goalkeeper Jordan Pickford after Sanchez's 13th-minute pass had carved a highway through the home defense.

However, Sanchez put Arsenal ahead in the 19th minute when he got ahead of Lamine Kone to head home Alex Oxlade-Chamberlain's cross.

Ozil should have made it 2-0 seven minutes before halftime after running on to Oxlade-Chamberlain's ball over the top, but did not get enough on his lobbed attempt to let the advancing Pickford and his team-mates off the hook.

After the break, Oxlade-Chamberlain squandered another golden opportunity after being played in behind a square defense once again and Sanchez was astonished not to be awarded a 62nd-minute penalty after going down under Kone's challenge.

Referee Martin Atkinson, however, did point to the spot at the other end two minutes later after Duncan Watmore had got away from defender Shkodran Mustafi and been tripped by 'keeper Petr Cech, and Defoe converted from the spot.

The respite was fleeting as Giroud steered home Kieran Gibbs' 71st-minute cross to restore his side's lead and then headed home Ozil's cross five minutes later.

Sanchez converted from close range after Gibbs' shot had come back off the post to complete a miserable afternoon for Sunderland.