The game sparked into life with a controversial opener on 37 minutes when Sebastian Larsson’s cross was played on by Cameron Jerome, and Lee Bowyer’s header was allowed to stand despite a hint of offside.
Roque Santa Cruz headed the wrong side of the post as Rovers fought back, but they had the post to thank for keeping them within one goal when Larsson clattered the upright from distance.
Jason Roberts then headed over, but deep into added time at the end of the first half Rovers did level matters when David Hoilett stole possession from Liam Ridgwell and rounded Ben Foster before rolling the ball into an empty net.
Larsson continued to be the dangerman for the visiting Blues and he brought another smart save out of Paul Robinson with a free-kick, while at the other end Santa Cruz headed against the crossbar.
And Blues goalkeeper Foster then ensured a point for his side by denying Martin Olsson late on.