DOHA, Qatar - Samantha Stosur and Marion Bartoli took a step closer to an all-star semifinal clash at the Qatar Total Open on Thursday, dismissing some very dangerous opponents in straight sets to reach the quarterfinals.

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Stosur, the No.3 seed at the Premier-level tournament, was the first to advance, taking out Petra Cetkovska, 63 62. Cetkovska, who had beaten No.13 seed Ana Ivanovic en route to the third round, had four Top 10 wins to her name going into the match, but was no match for the World No.5 on the day.

"I played a good match, quite solid, and did what I had to do," Stosur said. "I served well and returned well, which put pressure on her service games. As it went on I felt I was getting further and further ahead. I felt pretty good."

After a disappointing Australian season, losing early at all three tournaments she played Down Under, the Australian No.1 was happy to be finding her range again. "It's nice to win back-to-back matches again. This is a big event for us. It's a good feeling, and I hope I can keep it going for a few more days."

Awaiting Stosur in the quarterfinals is Monica Niculescu, who recovered from 5-2 deficits in the first set and in the ensuing tie-break to get by Ukrainian qualifier Kateryna Bondarenko in a tight straight-setter, 76(5) 64.

"I didn't start well but I started hitting many slices on the forehand and that helped me, because if I were hitting flat she would have liked that," Niculescu said of Bondarenko. "I think I got a little lucky with the wind sometimes too. It was really tough actually, I'm just happy I survived the match today."

Stosur is 2-0 against Niculescu, winning both meetings in straight sets.

"I played Sam a few years ago in Stanford and she won quite easily, then I drew her again right after that in LA and she beat me even more easily!" Niculescu said. "But I've improved since then. I've been winning a lot more matches and I'm confident. I'll give it my best shot when I play her and I'll make sure I have fun."

"I'll do the same warm-ups as I usually do, though I'm sure my coach Dave will throw in a few more slicey dicey shots," Stosur said. "There will be different shots coming over the net, but at the end of the day I've just got to worry about what I'm doing with them. You've got to play the ball that's there to hit."

Bartoli, the No.5 seed, reached the quarterfinals at night with a 63 63 win over Tsvetana Pironkova. Pironkova had seven Top 10 wins to her name going into the match but Bartoli went on some four-game runs in both sets - from 1-2 to 5-2 in the first set and 0-1 to 4-1 in the second set - to take complete control.

Next for Bartoli is Lucie Safarova, who followed up her second round upset of No.2 seed Caroline Wozniacki with a 76(6) 63 third round upset of No.14 seed Svetlana Kuznetsova, coming from double set point down in the first set tie-break then rallying from an early break down in the second set.

"I did very well last night against Caroline and followed that up with a very tough match against Svetlana today," Safarova said. "It was a very close first set. I'm glad I won it and carried the momentum until the end of the match.

"Everything is together for me this week. I feel very good on serve and it's helping me to win points in key moments. I hope to keep it going."

Bartoli leads Safarova in their head-to-head series, 4-1, although they were 1-1 in 2011 - Safarova won handily in Kuala Lumpur, 61 64, while Bartoli saved match point in a 63 36 76(7) win at Eastbourne (she went on to win the title).