(CNN) -- Nikolay Davydenko is emerging as a serious contender for 2010 after upsetting world No. 2 Rafael Nadal in the final of the Qatar Open on Saturday.
The Russian followed up his semifinal victory against top-ranked Roger Federer as he came from behind to triumph 0-6 7-6 (10-8) 6-4 against the Spaniard in a match lasting two hours and 43 minutes.
Seeded third in the absence of Novak Djokovic, Andy Murray and Juan Martin Del Potro, the world No. 6 saved two match-points as he clinched his 20th ATP Tour title in Doha.
Davydenko this week repeated his victories over Federer and Nadal from the 2009 season-ending ATP World Tour Finals in London, where he beat Del Potro in the final.
Meanwhile, defending champion Marin Cilic will play Swiss third seed Stanislas Wawrinka in the final of the Chennai Open in India on Sunday.
The Croatian defeated fourth-seeded Serbian Janko Tipsarevic 6-1 6-3 on Saturday, while Wawrinka beat Israeli fifth seed Dudi Sela 6-4 2-6 7-5 in the other semifinal.
Spain won the Hopman Cup for the third time, beating Great Britain 2-1 in the final in Australia as world No. 4 Murray was upset by 16th-ranked Tommy Robredo in the men's singles rubber.
Laura Robson, 15, had given Britain hope of a first title in Perth with a shock 6-1 7-6 (8-6) win over Maria Jose Martinez Sanchez, but Robredo then came from behind to triumph 1-6 6-4 6-3 as Murray dropped his first sets of the week.
The Spaniards then clinched the title with a 7-6 (8-6) 7-5 win in the doubles.