Just three days after their European tie ended all square, both teams were back at the Emirates to do battle for league points.
Recalled striker Peter Crouch gave Liverpool the lead.
Pepe Reina’s long ball was hooked on by Yossi Benayoun, and Crouch manoeuvred the ball into a shooting position before finding the bottom corner with a well-hit effort on 42 minutes.
However, Nicklas Bendtner equalised for the title-chasing Gunners on 54 minutes. The Danish striker ran from deep to plant an easy header past a stranded Reina from Cesc Fabregas’ floated free-kick.
The result means Manchester United, who play at Middlesbrough on Sunday, are five points clear at the top of the table.