Colin Montgomerie gingerly plucked his ball from the hole on the 18th green after taking the lead in the Deutsche Bank SAP Open near Heidelburg but fears he may be able to complete the job in the final round tomorrow.
After a 65 to go 17 under par, he heads defending champion Tiger Woods by a shot and is due to play with him in a final pairing showdown at St Leon-Rot tomorrow.
But despite his dazzling round the Scot goes into the concluding 18 holes "seriously concerned" back trouble will stop him giving the world number one a run for his money - the £280,000 first prize cheque,
Montgomerie twice took time out for treatment while keeping alive his hopes of a first-ever victory over Woods. He said: "If I get some flexibility in my back I have a chance of competing.
"I have a very weak back. I never thought my career would come to this, but I'm seriously concerned that I will not be able to compete."
The 38-year-old was doubtful before the start of the £1.6million tournament and when he felt more pain bending over on the third green he admitted: "I never thought I was going to continue."
But Australian physiotherapist Dale Richardson came to his aid with embrocation at the sixth, then some more manipulation after the ninth hole.
Montgomerie took pain-killing tablets to go with the four he took before play and to achieve the second best score of the round in the circumstances was phenomenal.
Woods had six birdies and a first hole eagle in his 64, which keeps him as favourite for what would be a third win in four years at the event.
Montgomerie is on the 17 under par mark of 199 and Woods 16 under exactly as he was 12 months ago.
Justin Rose, the 21-year-old from Hampshire who with three wins already this season has totally shaken off the troubled start to his professional career, lies third, but even with a 66 he is three behind Montgomerie. Greg Owen is on 12 under par.