(CNN) -- Third seed Agnieszka Radwanska crashed out of the Kremlin Cup after she slipped to a straight sets, 6-3 6-3, defeat to Russian Maria Kirilenko in Moscow.
Russian Maria Kirilenko reached the second round of the Kremlin Cup with victory over Agnieszka Radwanska.
The world number 10 from Poland lost her first service game and was unable to capitalize in the eighth as home favorite Kirilenko, who is ranked 61st in the world, saved four break points.
Radwanska was then unable to hold serve and lost the first set to the unseeded Russian before she received treatment for a thigh problem.
Kirilenko was able to capitalize on any weakness shown by Radwanska in the second set as she broke her opponent in the second game on the second set.
Radwanska missed a chance to break back in the seventh game and Kirilenko admitted she had good understanding of her opponent.
"I have played against Radwanska three times before and I won twice so I can say I actually like to play her -- she's not very aggressive and I always have enough time to hit winners," Kirilenko told the Kremlin Cup Web site.
"Everybody plays at a rather high level. To score success you need to keep showing your best tennis, which I'm trying to do in every match."
The elimination of Radwanska means that Jelena Jankovic and Vera Zvonareva are the only two players in contention for the last spot for the WTA Championships in Doha next week.
Kirilenko's victory has set up a second-round tie with world number 31 Aleksandra Wozniak of Canada.
Kirilenko added: "I don't know her really well. We just hit a couple of times together. I know she is a very aggressive player. The match will show it all."
Elsewhere, qualifier Evgeniya Rodina claimed victory over sixth-seed Elena Vesnina 6-1 3-6 6-2 in an all-Russian contest at the Olympic Stadium.
Hungary's Agnes Szavay progressed to the second round after Italian fourth seed Flavia Pennetta was unable to complete their match despite winning the first set.
Meanwhile, in the men's section, local favorite Marat Safin opened his final Kremlin Cup campaign by ousting defending champion and Shanghai Masters winner Nikolay Davydenko in the first round.
Safin, the runner-up in last year's final, came from a set down to win 4-6 6-4 6-2 and end Davydenko's bid for a fourth title in the Russian capital.
The 29-year-old, who retires at the end of the season, produced 10 aces and a better all-round game against his 28-year-old opponent to win in a little under two hours.