Tendon injury for Istabraq Three-time Smurfit Champion Hurdle winner Istabraq suffered a tendon injury when attempting a record fourth success in the Cheltenham contest on Tuesday, it emerged today.Jockey Charlie Swan felt uneasy on the Aidan O`Brien-trained gelding after he had jumped just one flight and after taking the second hurdle decided to pull the 2-1 favourite up.In his post-race examination, vet John Halley found that Istabraq had damaged the equine equivalent of an Achilles tendon in his hock but has no doubt that in time he will make a full recovery.Halley thought that the injury occurred either jumping off or jumping the first hurdle.In a statement to PA Sport O`Brien said: 'Istabraq spent a very comfortable night in the racecourse stables, ate up well last night and seems in good form this morning, but is understandably stiff on his off-hind.'He will travel home to Ballydoyle with Darapour this evening and will be re-examined by John Halley tomorrow morning.'We all wish to express our sincere thanks to all those who showed so much concern for the horse`s well being and we were touched by the number of faxes and e-mails we received.'Owner J P McManus added: 'I think he has obviously run his last race.'I think it is asking a lot to have another one as good.'