Madrid started 2010 just two points behind their arch rivals and could have taken over top spot, but poor away form, which has seen them return from trips to Osasuna and Athletic Bilbao with just one point and no goals scored, has undermined their efforts.
Diarra said: "We need to improve our away performances and continue winning in the Bernabeu. We were unable to score in each of our last two league matches away, but such things can happen in football.
"Since returning from Bilbao we have been working hard to improve and to be able to score in our upcoming matches."
Nevertheless, the France international insists Barca's advantage is nothing to be worried about.
"A five-point lead for Barcelona is only a matter of two games. Things can change quickly in football," he said.