Joey Barton's free-kick secured a point for Rangers but they lost defender Richard Dunne and midfielder Jermaine Jenas to injuries while winger Junior Hoilett was also struggling by the end.
"It was difficult, we lost a couple of key players with injuries," said Redknapp.
"Jermaine Jenas did his hamstring, Richard Dunne had to come off with a back injury at half-time and then Junior Hoilett did a hamstring.
"We'd used all our substitutes by that point so we were effectively down to 10 men and 1-0 down so it didn't look very good. I thought we were going to end up with about eight men on the pitch.
"At that stage we'd have taken a point so in the end it was a great result for us."