Kim Clijsters and Justine Henin were forced to draw on their vast experience to avoid being eliminated from the Brisbane International on Thursday.
The two Belgians, both back on the professional circuit after retiring from the sport, scraped through their quarter-finals to remain on course for a possible showdown in Saturday's final.
Henin advanced after downing Hungarian Melinda Czink 6-2, 3-6, 7-6 while Clijsters overcame a second-set wobble to beat Czech Lucie Safarova 6-1, 0-6, 6-4 in one of the major lead-up events before this month's Australian Open.
"That's the kind of match that I need," Henin, playing her first tournament in 20 months, told reporters.
"I came here to play matches and that's what I have done so I have no complaints."
Henin, a seven-times grand slam winner, appeared to be in cruise control when she steamed through the opening set in just 31 minutes but Czink took the second before forcing a tiebreak in the third.
The 27-year-old will now play Ana Ivanovic in Friday's semi-finals after the Serbian beat Russian teenager Anastasia Pavlyuchenkova 6-2 7-6.
"It's exciting to be able to play so many good matches and now Ana, that is the kind of match that I love, it's a great feeling," Henin said.
Clijsters, with her daughter Jada watching from the stands, said the experience of winning last year's US Open helped her regain her composure after she completely lost her way in the second set.
"When I lost that set 6-0 I said 'forget about it' and I just refocused," Clijsters said.
"She's beaten a lot of good players in the past so coming out here I knew I was in for a tough match."
Clijsters will play Andrea Petkovic in the semi-finals after the German posted a comfortable 6-4, 6-2 victory over Slovakia's Daniela Hantuchova.
"I am happy to play her, I am new on the tour, I want to see where I stand," Petkovic said of her matchup with Clijsters.
"I am not scared. If she kills me, she kills me, we will see."
In the men's event, defending champion Radek Stepanek beat American Wayne Odesnik 7-6 6-1 to ease into the last four.
The Czech will play Gael Monfils after the Frenchman ousted American James Blake 3-6 6-3 6-4.
