QPR started the brighter of the two sides at Loftus Road, with their first chance falling to Bobby Zamora. Adel Taarabt crossed from deep but the England international was unable to keep his effort on target.
Taarabt went on to find the net as QPR turned their domination into a goal in the 22nd minute. The Moroccan international collected possession 35 yards from goal, before tricking his way past Arsenal defender Thomas Vermaelen and shooting past Wojciech Szczesny from distance.
However, the visiting Gunners drew themselves level in the 37th minute courtesy of England international Theo Walcott. Skipper Robin van Persie threaded a pass through to Walcott, who scored at the second attempt after his initial effort had struck the post.
Both sides created chances to take the lead after the break, but it was the home side who grabbed the third goal of the match in the 66th minute. Jamie Mackie beat Vermaelen to the ball, before crossing for Diakite to claim his first goal for the R's.
Arsenal pushed for their second equaliser of the match but they were unable to find a route past Paddy Kenny in the home goal.