Serena Williams emerged from an error-strewn 6-2 7-6 (9/7) victory over Maria Sharapova to book a meeting with Victoria Azarenka in the final of the Brisbane International.
Williams served up seven aces but also produced the same number of double faults of which her Russian opponent made eight.
Both women were deserted by their serves, with the pair completing 10 breaks between them in a match lasting a little under an hour and three quarters.
The American broke in the sixth game of the match for 4-2 before going on to hold, with a double fault by Sharapova handing the world number one the set 6-2.
Neither woman could hold serve but nor could Williams see the match out, allowing Sharapova back in when serving for the match at 6-5 as the Russian forced a tie-break.
Williams moved to 6-5 and match point which she failed to capitalise upon before finally going through at 9-7.
Azarenka overcame a poor start to post a 1-6 6-3 6-4 victory over former world number one Jelena Jankovic.
The Australian Open champion dropped her first three service games and committed constant unforced errors as her opponent clinched the first set in less than half an hour.
However, she broke for a 2-0 lead in the second and from thereon in settled down and forced a deciding set.
The Belarusian moved to 5-1 only for Jankovic to win three consecutive games but Azarenka held her nerve and managed to serve it out with her second match point.
In the men's competition, Roger Federer stormed into the semi-finals as he dismissed Marinko Matosevic 6-1 6-1 in just 58 minutes.
The Swiss served nine aces and broke serve five times in the pair's first meeting.
Federer, who is also through to the doubles semi-finals with Nicolas Mahut, is looking to win his 78th tour-level title this week.
Next he will face world number 34 Jeremy Chardy, who ended the run of Australian wild card Samuel Groth with a 7-5 6-4 win in 69 minutes.
"Tonight I felt very good against Matosevic who can play very dangerous," said Federer.
"He's got a good enough serve and return as well. But I was able to control most of the match except the very beginning. For that, I'm very happy."
Of Chardy, he said: "He plays very aggressive on the hard courts.
"I remember seeing him play really well in Cincinnati, which is similar to here."
Second seed Kei Nishikori set up a semi-final with home favourite Lleyton Hewitt.
The Japanese player edged Marin Cilic 6-4 5-7 6-2 to book a last-four meeting with Hewitt, who eased to a 6-4 6-2 win over qualifier Marius Copil.
It is the second successive year Nishikori has reached this stage but it was done the hard way, the match lasting two hours and 37 minutes in scorching conditions.
Former world number one Hewitt, by contrast, took just an hour and 12 minutes to defeat Copil, who had upset Gilles Simon on Thursday.