Germany's Angelique Kerber carried her good form into Doha by upsetting the ninth seeded Sabine Lisicki in three sets in the first round of the WTA Qatar Open.
It was the fourth time in as many matches that Kerber had got the better of her compatriot, who is ranked 14th in the world and considered as one of the rising stars of the game.
"She is a great player who is also a good friend, so it's not easy playing against her," Kerber, who won the Paris Indoors last week, said after her 4-6, 6-4, 6-1 victory.
"We travel together and live in the same hotels, but I was focused on my game."
Kerber's form has been nothing short of spectacular recently, the German reaching at least the semi-finals in six of the past 10 tournaments she played before winning her first WTA title in Paris where she beat Marion Bartoli of France in the final.
"I am really playing well, but this is a big tournament with many stars playing, but I will really try my best," said the world's 22-ranked player.
The top eight players in the field have been given first round byes and will see action their first action today, with the world No 1 Victoria Azarenka, of Belarus, and Caroline Wozniacki, of Denmark, the favourites.
In other matches yesterday, Petra Cetkovska beat Petra Martic 7-6, 7-5. Sorana Cirstea had a fairly easy round defeating Jarmila Groth 6-4, 6-1 while Klara Zakopalova lost to Anabel Medina Garrigues 6-4, 6-1.
The upcoming Lucie Safarova, meanwhile, created an upset of sorts by winning her match with Urszula Radwanska 6-3, 6-4.