Brentford had the first chance of the game when Glenn Poole and Sam Wood linked up well on the edge of the Rochdale box which resulted in Poole firing just wide of the far post.
But it was the visitors who had the best chance to take the lead in the opening exchanges when Bees keeper Ben Hamer fumbled a low cross by Chris Dagnall, but Adam Rundle was unable to turn in the loose ball.
New on-loan striker Dean Bowditch took little time to adapt to his new surroundings and linked up well with striker partner Charlie MacDonald. Bowditch played in MacDonald on the edge of the Rochdale box, but he fired his shot straight at Sam Russell.
Although Brentford bossed the play for the opening half-an-hour it was Rochdale who took the lead through Rory McArdle.
McArdle was unmarked inside the area and rose highest to head a Tom Kennedy corner past a helpless Hamer.
Hill's side doubled their lead five minutes before the break when Brentford defender James Wilson slipped in the box, allowing Will Buckley to fire his low shot into the far corner of the net - his fifth goal of the season.
Brentford were back in the game five minutes into the second half when Poole crossed from the left and Bowditch dived in at the far post to head home on his debut.
MacDonald then had a glorious chance to level the scores when he was played in by Bowditch, but Russell was able to keep him out.
Russell was also on hand to keep out a speculative long-range effort from sub Mark Phillips.
The hosts did their best to find an equaliser but Rochdale managed to hang on and claim all three points.