Arsenal remained sixth in the Premier League standings after beating Queens Park Rangers 2-1 at the Emirates.
Alexis Sanchez, 26, scored in the 37th minute and put Gunners into the lead.
The north Londoners were reduced to 10 men when Olivier Giroud was sent off for headbutt on Onuoha, before Tomas Rosicky made it 2-0 with a fine finish in 65th minute.
This victory brings Wenger’s 400th in the Premier League, while QPR have now lost all nine away league matches thus far.
Here are some of the best reactions from the Professionals,
Brilliant again from Sanchez. He’s a player and a half!
— Gary Lineker (@GaryLineker) December 26, 2014
A good way to end my birthday watching the lads get 3 points. Well done! Thanks for all the tweets and wishes today
— Aaron Ramsey (@aaronramsey) December 26, 2014
Disappointing result..could have nicked a draw towards the end with a bit of luck! Ps..apologies for feeling the hairs on Girouds neck back!
— Rio Ferdinand (@rioferdy5) December 26, 2014
Alexis Sanchez beats QPR.
— Piers Morgan (@piersmorgan) December 26, 2014