Lions fear Sam Warburton is out of final Test

Captain is a significant doubt for the biggest game of the rugby year after suffering a hamstring injury 14 minutes from the end of 16-15 defeat to Wallabies

The Lions are licking any number of wounds after narrowly failing to win a first Test series in the southern hemisphere since 1997, but one wound in particular will be tormenting them ahead of next weekend's third and final meeting with the Wallabies in Sydney. Sam Warburton, their captain, is a significant doubt for the biggest game of the rugby year after suffering a hamstring injury 14 minutes from the end of yesterday's 16-15 defeat.

While the Welsh flanker, the Lions' best player in a contest that generated infinitely more tension than exhilarating rugby, will not know until tomorrow how his prospects are shaping up, there was immediate concern amongst the Lions hierarchy. They can ill afford to forfeit their leader, so soon after losing a former Lions skipper in Paul O'Connell to a broken arm.

"I've never had a hamstring injury before," said Warburton, who had to be helped off the field by two members of the Lions' medical staff. "If it was another problem with my knee, I'd understand more about it. This is new to me and I don't think the medics will make any firm diagnosis for at least 24 hours, maybe 48 hours. I'm desperate to play in Sydney. We'll just have to see how it goes."

If Warburton is ruled out of the decider, another Welsh breakaway specialist, Justin Tipuric, will be the hot favourite to win a first Lions Test cap in the back row. As for the captaincy, there will be only one candidate: the great Irish centre Brian O'Driscoll, now on his fourth and final tour and the emotional centrepiece of this squad.

Meanwhile, the citing commissioner, Glenn Newman of New Zealand, was said to be looking into a small number of incidents that may or may not result in disciplinary action. The most obvious one concerned the Lions prop Mako Vunipola, who made contact with Adam Ashley-Cooper – scorer of the game's only try – as the Wallaby centre chased a first-half restart. Ashley-Cooper was left on the ground, with the Australians claiming he had been illegally charged.

Warren Gatland, the Lions' head coach, did his best to put on a brave face and showered sympathy on the full-back Leigh Halfpenny, who missed a long and wickedly difficult penalty with the last kick of the game – a kick that would have rendered the Sydney Test irrelevant.

"I've seen Leigh kick them from there before," Gatland said, "but he just didn't strike that one well enough. He understood the significance of the shot, he had a chance to be a hero in that moment and he's disappointed he missed, but I don't think I'll have to do anything to pick him up. He's such a professional and he's still kicking incredibly well.

"He failed with two long kicks out there, the first of which hit the crossbar, and that's the difference at this level. But actually, I think losing Sam was the blow that really hurt us. His injury forced us to reshuffle things in a way we hadn't planned."