Nikolay Davydenko reached the Qatar Open quarter-finals by beating fourth-seeded Mikhail Youzhny 7-5, 6-3 on Wednesday.
The former third-ranked Davydenko has struggled in recent years with injury, but the Russian combined a consistent first serve with aggressive play to eliminate the 25th-ranked Youzhny.
Davydenko broke his opponent to take a 6-5 lead in the first set and won when Youzhny hit a forehand into the net.
Davydenko kept the momentum going into the second set, forcing Youzhny to save a break point in the first and third games. At 2-2, Davydenko won three successive games to take control.
"Really today was (a) tough match,'' said Davydenko, who won the tournament in Doha three years ago.
"Maybe we didn't start well with so many mistakes. I know against Russians when you play in second round, it's not easy."
Ahead of the season-opening tournament, the 44th-ranked Davydenko said he was targeting a place in the top 20 this year after failing to win a tournament in 2012.
"If I really concentrate and (practice) and play, I want to see results," Davydenko said.
Gael Monfils defeated third-seeded Philipp Kohlschreiber of Germany 6-4, 2-6, 6-4.
Aussie Open approaches
World number nine Janko Tipsarevic of Serbia opened his campaign in the ATP Chennai Open on Wednesday with an emphatic win that lifted him into the quarter-finals.
Tipsarevic, seeded second behind world number six Tomas Berdych of the Czech Republic in the $430,000 season opener, brushed aside Frenchman Edouard Roger-Vasselin 6-2, 6-3 in a second-round match.
Tipsarevic, who lost to Canadian Milos Raonic in last year's final, was delighted at winning his first match in the tournament after being given a bye in the first round.
"It is never easy to win the first match, but I think I played reasonably well to win in straight sets," said the 28-year-old Serb.
"I did not drop my serve and took advantage of the unforced errors my opponent made, especially in the first set.
"If I win in Chennai, it will be a real morale booster for Australia"
"This is my fifth visit to Chennai and I hope I can win the title for the first time this year. I know other players are already looking at the Australian Open, but I look at it differently.
"If I win in Chennai, it will be a real morale booster for Australia," said Tipsarevic, who beat US Open and Olympic champion Andy Murray at an exhibition event in Abu Dhabi last week.
The Australian Open, the year's first Grand Slam, starts in Melbourne on January 14.
Tipsarevic next plays eighth seed Go Soeda of Japan, who overcame a spirited challenge from Indian qualifier Prakash Amritraj before winning 7-6 (7/2), 3-6, 6-4 in two hours and 30 minutes.
Soeda, a semi-finalist last year after making the main draw as a lucky loser from the qualifying round, said he was fortunate to be still afloat in the tournament.
"I did not play very well today and made many mistakes from the baseline," said Soeda, Japan's number two player after Kei Nishikori.
"I will have to play better if I am to compete against a strong player like Tipsarevic."
Sixth seed Robin Haase of the Netherlands was knocked out in the second round by Aljaz Bedene of Slovenia, losing 7-5, 6-3.
Bedene's quarter-final opponent will be fourth seed Stanislas Wawrinka of Switzerland, who defeated Cedrik-Marcel Stebe of Germany 6-4, 6-3 in the last singles match of the night.
Berdych and third seed Marin Cilic of Croatia, handed byes in the first round along with Tipsarevic and Wawrinka, will join the action on Thursday.
Berdych meets Indian wildcard Somdev Devvarman, while Cilic takes on Sergiy Stakhovsky of Ukraine.