Venus Williams will play Alize Cornet in the final of the Dubai Duty Free Tennis Championships after the world number 26 from France secured a hugely impressive straight-set victory over Serena Williams.
Eariler in the day Venus had booked her place in the final with a 6-3 6-2 win over Caroline Wozniacki, in which she dominated the former world number one from Denmark from start to finish with her heavier, and sometimes cleverly angled, driving.
"To come into a tournament with such a strong draw and to play a former number one now and get through is a wonderful result," said Venus.
The doubts have been whether Venus, who still battles against the side effects of an immune deficiency, has regained the endurance to produce back-to-back wins, and, although she has yet to be taken to three sets, the evidence is hopeful.
She made the ideal start, breaking Wozniacki's serve in the first game, and consolidating it with a hold, despite having trouble landing her first delivery as often as she might have liked.
But breaks of serve became commonplace, and the match often hinged on who could get the best blow in first in the rallies, something which Venus still very well equipped to do.
Wozniacki, who has been in good form herself this week at a tournament she has won before, lacked consistency on the forehand wing early on, and was twice unable to snatch game points which might have placed more score pressure upon her free-hitting opponent.
Twice her father coach Piotr came on court to offer some of his demonstrative advice, but it did not halt the direction of the match.
This accelerated after Venus had clinched the first set after a game of three deuces by punishing her opponent's second serve.
She then took the first three games of the second set and the end soon came with a flurry of typically fierce drives which Wozniacki could not contain.
There had been the chance that Venus could play her sister for the first time since 2009 when they met in Doha but Cornet was in superb form as she secured a 6-4 6-4 win over Serena.
The American world number one struggled throughout, failing to make inroads into the Cornet serve and producing some uncharacteristic unforced errors.
Cornet played one of the matches of her life as she took the first set with ease before nerves appeared to get the best of her in the second as Serena threatened to force her way back into the match.
Serena was serving to stay in the match at 3-5 and somehow managed to save three match points before eventually coming through and forcing Cornet to serve for the win.
However, yet more unforced errors and some superb serving from Cornet saw her complete a memorable victory in 84 minutes.
Roger Federer is planning to tap coach Stefan Edberg's deep well of experience to try some new things in his quarter-final showdown with Andy Murray at the Australian Open.
The record 17-time Grand Slam champion cruised into the last eight at the year's opening Slam with a consummate straight-sets victory over Jo-Wilfried Tsonga on Monday.
The Swiss great, seeded six, rolled back the years as he swept past the French 10th seed 6-3, 7-5, 6-4 in one hour 52 minutes in an evening match on Rod Laver Arena.
Federer has now reached his 11th consecutive quarter-final in Melbourne and equalled the record of 41 Slam quarters with American Jimmy Connors as he set up a rematch of last year's semi-final which Murray won in five sets.
Federer, who is working with the six-time Grand Slam champion Edberg for 10 weeks, said he will draw on the Swede's knowledge to devise tactics for the match with Wimbledon champion Murray.
"It's not going to hurt. Yeah, it could be very helpful. We'll talk about it a little bit about the Murray match," he said.
"It's just a different perspective. He did things his way back in the day and you can take so many things from his experience.
"I want to maybe try out a few things that worked for him and try out a few things that he thinks would work out for me this time around.
"Sure, we'll discuss it, assess it, but he's here now more for just support, making me feel comfortable, giving me right advice, pre-match, post-match, discussing it with Severin Luthi my coach."
Federer's quarter-final with Tsonga went to five sets in last year's Australian Open but the Swiss sixth seed was always in command with his aggressive display, dominating the net exchanges.
Federer broke Tsonga's service three times, and only had one break point against his own serve. He won 88 percent of his first-serve points and more than twice the number of winners (43) than errors (21), in a clinical performance.
Federer also won 34 of the 41 net points, illustrating his plan to take the game to Tsonga.
"I thought I played really well tonight and clearly against Jo-Willy you have to bring your best game because he dictates play and I thought I did well dictating a lot of the plays," Federer said.
"Jo makes you play an aggressive game because if you don't he'll come and it's tough to pass him.
"Tactics worked well and we spoke about it before the match. I don't go unprepared into matches like I used to."
Roger Federer will play Andy Murray in a much-anticipated quarter-final showdown at the Australian Open after tossing aside Jo-Wilfried Tsonga in straight sets on Monday.
World No1 Rafael Nadal also won through to the last eight where he will face rising Bulgarian star Grigor Dimitrov in Wednesday's quarters in the top half of the men's draw.
Record Grand Slam champion Federer had few problems with 10th-seeded Frenchman Tsonga, winning 6-3, 7-5, 6-4 in one hour 52 minutes in the fourth-round evening match on Rod Laver Arena.
Federer's comfortable victory over the 2008 Melbourne finalist set up a rematch of last year's semi-final which Murray won in five sets.
Wimbledon champion Murray was taken to four sets and smashed his racquet in frustration before finally ending 'lucky loser' Stephane Robert's dream run.
In Monday's other men's action, Nadal received two time violation warnings for slow play as he fought off a spirited challenge from Japan's Kei Nishikori, 7-6 (7/3), 7-5, 7-6 (7/3) in three hours 17 minutes.
Nishikori, showing the effects of working with new coach Michael Chang, pressed Nadal all the way and had his chances to take sets off the top seed only to lose the big points in the match.
Dimitrov became the first Bulgarian man to qualify for a Grand Slam quarter-final and said he fancied his chances against Nadal after ousting unseeded Spaniard Roberto Bautista Agut 6-3, 3-6, 6-2, 6-4.
Federer has now reached his 11th consecutive quarter-final at the Australian Open and equalled the record of 41 Slam quarters held by American Jimmy Connors.
Federer's quarter-final with Tsonga went to five sets in last year's Australian Open but the Swiss sixth seed was always in command with his aggressive display, dominating the net exchanges to win in straight sets.
"I'm very pleased. I didn't get broken and that was against a great player. So, yeah, I'm extremely happy how things went for me tonight," Federer said.
"I was able to play my game, offensive, mix it up, come to the net. I was surprised that things worked out for me."
Murray easily won the first two sets but passed up three match points in the third – and totalled a racquet in a fit of pique – before beating Robert, 6-1, 6-2, 6-7 (6/8), 6-2. Robert, at 119, has a ranking 115 places below the Scot, a three-time finalist in Melbourne.
The Frenchman, 33, was the first lucky loser – someone who loses in qualifying, but gains a place via a withdrawal – to reach the tournament's last 16, and the oldest man since Andre Agassi in 2005.
"He's a fun player to watch but not fun to play against," said Murray. "He made it very tricky for me, he plays all the shots very unorthodox."
Nadal called for more understanding from umpires over time warnings as he praised Nishikori's performance.
"Kei played a fantastic match. Just a few mistakes in some moments that were tough ones. But he played very aggressive, he went for his shots," Nadal said.
"He came on court with determination to take the ball very early and go for the winners. It was just a tough match, a very important win."
Nadal was angered when he was called for an unsettling second time violation in between points by chair umpire Eva Asderaki at deuce while 4-4 at a critical time in the third set, but he regained his composure to go through on his second tiebreaker.
The 13-time Grand Slam champion did not dispute the 20-second rule in between points at Grand Slams, but rather took issue with the timing of the warning.