For Chris Gayle, the physical pain would have been trifling compared to the mental anguish. As soon as the West Indies captain felt the sharp pain at the back of his right thigh after completing the sharp, risky single to raise his hundred yesterday, he knew his team's chances of protecting their 1-0 lead in the series were out of his hands.
He had applied himself with the measured assurance that has been the hallmark of his batting since he came to the Test captaincy in South Africa in 2007. The foundation had been laid for an innings of similar importance to his eight and a half-hour 197 against New Zealand at Napier last December that guided the West Indies out of choppy waters towards a potentially winning position.
As CJ Clark, the physiotherapist, rushed on to the field and gave his early, later confirmed, prognosis that the hamstring was damaged, it was clear that Gayle's further participation would be minimal and compromised.
It meant that whenever he resumed his innings, he would do so virtually on one leg and with a runner. So it was in his second Test against South Africa at Cape Town just over a year ago and it contributed to a hard-fought loss.
His hope now was that it would not be until well into the following afternoon, if at all. At 211 for four, however, his concern deepened.
But the resolve of his team was evident in New Zealand and in the preceding Tests in Antigua and Barbados. Once again, two left-handed fighters, one with a long established reputation, the other quickly following his lead, filled the breach to thwart England. The partnership between Shivnarine Chanderpaul and Brendan Nash achieved the first goal just before the close, passing the 347 required to ensure England must bat again.
Gayle's relief was not difficult to imagine. The decision to strengthen the batting and leave the bowling in the care of one bowler of genuine Test quality, one who pays 46 runs for each of his wickets, another in his second Test and others who are principally batsmen has come in from widespread criticism. So has his laid-back leadership on the field as England have amassed huge totals in the last three Tests.
The fact is that the West Indies started the final Test in a series against reputable opponents ahead for the first time since they led Australia 2-1 in the Caribbean in 1999.
As far as Gayle is concerned, the ends will justify the means. His career has coincided with the most depressing period in West Indies history and he and his Australian coach, John Dyson, have stressed that, to come out of it, they must first break free of the mindset of defeatism.
Entering this Test, they had not been beaten for six Tests. Their dramatic victory in the first Test has given them the lead and they have more than once fought themselves out of tight corners to protect it. It is a rare and satisfying position but defeat here would be a decided setback. While they still have work to do, they are within sight of their objective.