Cape Town - Kevin Anderson handed Japan's Kei Nishikori a humiliating 6-0, 6-1 thrashing at the ATP Finals as the South African moved to the brink of a semi-final berth on Tuesday.
Anderson won the first 11 games and needed only 64 minutes to demolish the woeful Nishikori in a remarkably one-sided group stage clash at London's O2 Arena.
Having also won his opening match against Dominic Thiem in his debut at the prestigious season-ending event, Anderson is close to becoming the first African to qualify for the last four at the ATP Finals.
The 32-year-old's place will be secure if Thiem beats Roger Federer, or if Federer defeats Thiem in three sets later on Tuesday.
It was a landmark moment for Wimbledon finalist Anderson, who has set a new career-high of 47 victories in a calender year.
He will rarely have had such an easy outing as this one throughout his memorable 2018.
"It's amongst the best I've played. I did a really good job constantly applying the pressure and not letting up," Anderson said.
"I just felt I returned really well, made him hit a lot of shots off his serve. He wasn't getting too many free points.
"I was growing in confidence and he sort of probably was going a little the other way. So, from my side, I did a fantastic job throughout really."
Anderson won the Vienna final at Nishikori's expense in October before losing to the Japanese star in the Paris Masters four days later.
But the close nature of those matches was a distant memory as Nishikori, who had beaten Federer in straight sets on Sunday, put his hopes of a semi-final spot in jeopardy with this tame surrender.
Nishikori was at a loss to explain his performance, saying: "I played one of the worst matches this year. Today was a terrible match.
"I don't even know why I didn't play well. I was lost a little bit. I just didn't feel the ball.
"He played well, but something was wrong. I've got to fix it and try to be positive for next one."
Anderson's final group match is against Federer on Thursday, while Nishikori faces Thiem.
It has been a curious year for Nishikori as the former US Open finalist, troubled by a wrist injury, started 2018 losing to the world number 238 in a Challenger event in January and crashed to 39th in the ATP rankings in April after a prolonged slump.
The 28-year-old had climbed back to ninth in the world thanks to a strong second half of a campaign, featuring a semi-final appearance at the US Open.
His renaissance peaked when he handed former ATP Finals champion Federer his first straight sets defeat in the group stage of the tournament.
But Nishikori seemed to have nothing left after that effort.
Anderson is back in London just four months after losing his first Wimbledon final against Novak Djokovic, and this was the kind of dominant display that carried him to the title match at the All England Club.
It took Anderson just 31 minutes to complete his first set masterclass against Nishikori and he didn't take his foot off the gas.
Aided by 24 unforced errors from Nishikori, Anderson dropped just a solitary game in the second set as this beleaguered opponent narrowly avoided becoming only the second player to lose 6-0, 6-0 at the ATP Finals.
In the doubles tournament, Raven Klaasen and his New Zealand partner Michael Venus beat Nikola Mektic and Alexander Peya in a closely contested match.
They ran out 7-6 (7/5), 7-6 (7/5) winners in a match lasting 1 hour and 45 minutes for their first win in the tournament after losing to Jamie Murray and Bruno Soares on Sunday.
Results on the third day of the ATP Finals at London's O2 Arena on Tuesday (x denotes seeding):
Group Lleyton Hewitt
Kevin Anderson (RSA x4) bt Kei Nishikori (JPN x7) 6-0, 6-1
Roger Federer (SUI x2) v Dominic Thiem (AUT x6)
Raven Klaasen/Michael Venus (RSA/NZL x6) bt Nikola Mektic/Alexander Peya (CRO/AUT x7) 7-6 (7/5), 7-6 (7/5)
Juan Sebastian Cabal/Robert Farah (COL/COL x2) v Jamie Murray/Bruno Soares (GBR/BRA x4)