Victoria Azarenka of Belarus demolished Belgium’s Elise Mertens in straight sets to reach the semi-finals of the US Open on Wednesday.

The former world No 1 thrashed the 16th seed 6-1, 6-0 in just 73 minutes inside an empty Arthur Ashe Stadium.

“That was pretty good,” said Azarenka. “I felt that I made the court really big for her today, which worked really well,” she added.

Mertens, 24, failed to hold her serve once during the match and won only 19 percent of points on her second serve. The Belgian also hit 23 unforced errors, compared to Azarenka’s 11.

“I felt that I really executed my plan. I was going to try to use my speed, use my power of the ball so I tried to do some variation where I would get her out of balance,” Azarenka said.

The two-time Grand Slam winner, will renew her rivalry with Serena Williams in the last four on Thursday. Williams defeated Azarenka in the final of the US Open in 2012 and 2013.

The unseeded Azarenka is bidding to end a seven-year wait for a third Grand Slam title at Flushing Meadows.

Azarenka’s last Slam title came at the 2013 Australian Open, when she retained the crown she had won a year earlier. Her last appearance in the final of a tennis major was her US Open defeat to Williams that same year, which she lost in three sets. Azarenka also suffered an agonising loss in 2012, when she served for the match at 5-3 in the third set only to lose 7-5.

She became a mother in December 2016. A custody battle over her son has disrupted her career in recent years.

Azarenka is brimming with confidence after a run of victories which includes claiming last month’s Western and Southern Open tune-up event in New York.

She said she was benefitting from staying in a private house in New York, rather than one of the tournament’s pre-approved player hotels.

“My mom is cooking every night. That’s just a huge advantage, I think. Being able to play with my son in the garden and push him on the swings is important,” Azarenka said.

The Belarusian said she was enjoying tennis much more now than she ever did when she topped the rankings. During her US Open run this year she has been seen on court dancing a little to music blaring from the loud speakers.

“I was so upset and I couldn’t for a couple of days function normally because you get so overwhelmed and now it doesn’t bother me,” she said.

“I can really say that I can feel the moment and I am enjoying it,” Azarenka added.

She won the Western & Southern with a walkover after Japan’s Osaka withdrew due to a hamstring injury.

Osaka, the US Open’s fourth seed, plays American Jennifer Brady in Thursday’s other semi-final.