Colin Montgomerie and Tiger Woods will have the showdown the crowds had hoped for after a dazzling day's golf in Heidelberg today.
Woods fired a 64, but Montgomerie responded with a 65 to lead by one (17-under-par) going into the final round of the Deutsche Bank-SAP Open.
Padraig Harrington outstripped Darren Clarke as the leading Irish challenger. The Dubliner shot a 66 but at 9-under is unlikely to trouble the leaders. Clarke carded a 73 to slip to 8-under.
Montgomerie goes into the tomorrow’s final 18 holes "seriously concerned" back trouble will stop him giving the world number one, and defending champion, a run for his money.
Montgomerie, who twice took time out for treatment while keeping alive his hopes of a first-ever victory over Woods, 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 £1.6 million tournament and when he felt more pain bending over on the third green 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 is on the 17 under par mark of 199 and Woods 16 under exactly as he was 12 months ago.
He was also one behind then, but shot a 66 to Eduardo Romero's 77 and won by four.