Davydenko beat Roger Federer in the semi-finals on Friday
Russia's Nikolay Davydenko saved two match points as he fought back to beat Rafael Nadal 0-6 7-6 (10-8) 6-4 in a dramatic Qatar Open final in Doha.
Davydenko, who beat Roger Federer in the semi-finals, was in big trouble after the Spaniard won the first set but he took the second to a tie-break.
However, Nadal failed to take two match points, hitting one lamely into the net, and Davydenko levelled the match.
The Russian then fought back from 3-1 down to take the deciding set.
"I was just fighting. I never thought about winning. I didn't think I could win," said Davydenko.
"For every point I was fighting. And at the end it was just amazing."
Davydenko is enjoying the best form of his career. He also won the season-ending ATP World Tour finals in November, beating Federer and Nadal in the process.
Argentina's David Nalbandian is the only other player to beat Federer and Nadal in the same tournament on two occasions - at the Madrid Masters and Paris Masters in 2007.
Davydenko's victory in Doha came after a gruelling encounter which lasted two hours and 43 minutes and it was his 20th title.
The Russian's victory was all the more impressive because he was so outclassed by Nadal in the first set, winning just one point on the Spaniard's serve.
A see-saw second set went the distance, with Davydenko eventually taking the tie-break 10-8 after Nadal had wasted two match points.
Davydenko won the first point easily, but on the second the world number two earned himself a pressure-free forehand from inside the baseline, but inexplicably dumped it into the net.
Nadal broke first in the decider to claim a 3-1 lead, but Davydenko dug deep once again, slamming winners off both flanks as he closed out the match.
The defeat was a blow to Nadal as he gears up for the defence of his Australian Open title later this month.
The Spaniard said Davydenko deserved his victory.
"In this tournament I came back to play my best tennis for a long time," he said.
"I lost today but he played unbelievable tennis - he was just better."