David Weir and Daniel Cousin headed Rangers in front at Celtic Park but Scott McDonald added to his fourth-minute goal just before half-time.

And Barry Robson blasted home a 70th-minute winner from the spot after Kirk Broadfoot had hauled down McDonald.

The 3-2 win keeps Celtic in the Clydesdale Bank Premier League title race, putting them five points ahead with three matches fewer to play than Rangers.

Strachan told Setanta Sports: "After scoring the first goal it kind of spooked us. We sat a bit too deep but sorted it out in the second half and it worked well for us.

"Rangers are physically a big, big side and they have good deliveries. They were two good deliveries and great headers. We think we could do better, but when we played I thought we made some excellent chances."

Strachan is hopeful the injury that forced captain Stephen McManus off midway through the second half is not too serious.

"It's more of a tightness rather than that instant stab in the calf you get sometimes," he said.

Rangers manager Walter Smith praised his players for their "fantastic" effort three days after their UEFA Cup semi-final first leg against Fiorentina.

But he admitted they had conceded soft goals without injured goalkeeper Allan McGregor and the suspended Carlos Cuellar, whose centre-back partner Weir limped off with a groin strain.

Smith told BBC Radio Scotland: "I felt it was a decent game but I am a little bit disappointed to give Celtic the goals rather easily.

"It was poor defending from ourselves. That apart, our players did exceptionally well to come back from the early goal.

"But we are disappointed to lose the last goal, I think it was a contributory factor that Davie Weir had come off.

"With Christian Dailly, Amdy Faye and a new goalkeeper, we had a little bit of disruption in defence."