Wigan boss Roberto Martinez condemned Craig Gardner's foul on Franco Di Santo and thinks the striker may have suffered ankle ligament damage.[LNB] Birmingham midfielder Gardner went in on Di Santo with a foot raised in the final minute of Saturday's woeful Premier League goalless draw at St Andrew's and was given a straight red card by referee Mark Clattenburg.[LNB]Blues' four-goal leading scorer will have to serve a three-match ban, but Di Santo could be out for longer if scans show serious damage.[LNB]Martinez had a brief chance to assess the damage suffered by Di Santo, and explained it could be a bad blow.[LNB]He said: "I've just seen Franco Di Santo's leg and that's my worry. We have to see the extent of that injury.[LNB]"He has a couple of nasty cuts in his leg and by that you can see the challenge was really high.[LNB]"The referee had a clear view and was on top of the incident and my worry is the extent of the injury.[LNB]"The cut swelled up straight away and there could be a bit of ligament damage in his ankle, which is the worry.[LNB]"From where I was, Gardner's leading foot was really high and he gets the ball with the second foot.[LNB]"Nowadays you can't go into a challenge like that with your feet high.[LNB]"It was a reckless challenge with excessive force and it was a red card, but all I'm worried about is Franco's injury."[LNB]Birmingham manager Alex McLeish had no complaints with the sending-off.[LNB]McLeish said: "At the time I just thought it was two players together and you couldn't avoid a collision but I've seen it on video and we won't be appealing.[LNB]"I don't think it was a massively dirty tackle but when your studs are showing, it's come more and more into the English game.[LNB]"You might have got away with it a year ago but, when there are studs colliding with a player's leg, then the refs are clamping down on that in this country.[LNB]"It's been in international football for a long time but as long as everyone is consistent I don't mind. The ref was in a good position and, under the rules, he's made the right decision."[LNB]Martinez praised Charles N'Zogbia for the way he handed abuse from the Birmingham crowd after the collapse of his move to St Andrew's in the summer.[LNB]The Wigan boss said: "I thought he coped with it very well. I was never in doubt because he loves that sort of challenge.[LNB]"I think in football when you get the opposition crowd targeting you it's a football compliment because they see you as a threat, as someone who can win the game and I felt he took it in the manner.[LNB]"He was a threat, worked really hard and is slowly getting back to his best."[LNB]Birmingham are now unbeaten in 18 top-flight home games, equalling their best-ever run.[LNB]McLeish said: "I am proud of the record. There was a lot of pressure on us today due to the media coverage of the record.[LNB]"I felt it could be one of those occasion where people were waiting for you to end up with egg on your face.[LNB]"I am sure there were a lot of people predicting we would lose the record just because of all the hype but it was something we couldn't avoid and I told the players that.[LNB]"We put it aside and did everything in our powers to get the three points. We just couldn't get the ball into the net.[LNB]"There were some great set-piece situations, some great deliveries from Seb Larsson in the first half, but we're lacking that killer touch."