World number one Novak Djokovic had to dig deep in the opening set as he reached the quarter-finals of the Paris Masters with a 7-6(7), 6-1 win against Britain's Kyle Edmund on Thursday.
The 16-times Grand Slam champion, who has been slightly ill lately, was kept on his toes before racing to victory to set up a meeting with seventh seed Stefanos Tsitsipas after the Greek beat Australian Alex De Minaur 6-3, 6-4.
Serbian Djokovic bagged the first set on his seventh opportunity and he did not look back after breaking for 2-1 in the second with a booming forehand winner.
Fifth seed Dominic Thiem was knocked out in the third round when he lost 6-3, 6-2 to Bulgarian Grigor Dimitrov who will play his first quarter-final at a Masters event since Canada 2018.
Dimitrov, who had been struggling since reaching the semi-finals at the US Open, played brilliantly throughout, taking advantage of Thiem's fading condition after the Austrian won the title in Vienna last Sunday.
Dimitrov next takes on Chile's Cristian Garin, who beat local favourite Jeremy Chardy in three sets.
Later on Thursday, world number two Rafael Nadal, looking to lift the trophy at Bercy for the first time, takes on old foe Stan Wawrinka.
The Swiss, along with Frenchman Gael Monfils, De Minaur and Italian Matteo Berrettini, is vying for the remaining spot for the season-ending ATP Tour finals.
Top ranked Barty books berth in WTA Finals last four
World number one Ash Barty booked her place in the semi-finals of the WTA Finals on Thursday as the Australian made short work of Petra Kvitova, handing the Czech a 6-4, 6-2 defeat.
Barty needed to win to be sure of progressing having won one and lost one of her opening matches, and she did so in style as she dominated to win in 88 minutes against a tired looking Kvitova, who exits the competition with three straight losses.
"I felt like I executed really well tonight and I think overall I knew I had to come out here and play aggressively and play to win," said Barty.
"It was a really good match tonight and I'm really excited to have another chance to play here on this beautiful court."
Barty took the first set after breaking Kvitova in the fifth game, using her athleticism and movement around the court to put the Ukrainian under constant pressure.
The Australian continued her dominance early in the second set, breaking Kvitova twice in the first three games to establish a winning margin over the Czech, who racked up 31 unforced errors across the match.
Later in the evening, Belinda Bencic joined Barty in the last four after Kiki Bertens withdrew from their meeting after losing the first set to the Swiss.
Bertens, who came into the tournament after the first round as an injury replacement for Naomi Osaka, called for the doctor after losing the opening set and, after a brief consultation, headed for the locker room and a retirement.
"With Kiki, we were fighting a lot for coming here for the eighth spot for the WTA Finals, so it was nice to have a match for the semi-finals," said Bencic.
"But I'm sorry that maybe the gas ran out. It's the end of the season so everyone's exhausted and I wish her the best."
Bertens broke early in the opening set and surged ahead, only to surrender her own serve in the 10th game to allow Bencic to pull level.
The Swiss went on to claim the first set before an emotional Bertens withdrew.
"I'm super happy with how I fought in the first set, it was not easy," said Bencic.
"She was slowing the pace down well. It was tactically good from her, serving bombs, serving aces so it wasn't easy.
"But I'm happy with how I played and how I fought and I'm excited to be in the semis."
Andreescu pulls out of WTA Finals with knee injury
US Open champion Bianca Andreescu has withdrawn from the WTA Finals in Shenzhen, citing the knee injury sustained in her defeat by Karolina Pliskova as the reason for pulling out of the season-ending championships.
The Canadian suffered the injury three games into her meeting with Pliskova, and although she continued with a heavily strapped knee until the end of the first set, the 19-year-old was eventually forced to retire.
"I had a scan Thursday to check my knee after last night's match, and unfortunately the results show that I need to withdraw," Andreescu said.
"It was amazing to play here in Shenzhen at the end of this incredible season. I'm very disappointed to not be able to finish the year on my terms, but I am hopeful I will have more chances to play here in the future."
Andreescu will be replaced in the draw by Sofia Kenin from the United States, who will take on defending champion Elina Svitolina in the final round of matches in the purple group on Friday.
Svitolina has already secured her place in Saturday's semi-finals while Simona Halep and Pliskova will meet on Friday, both looking for a win that will take them into the last four.
Andreescu is the second player to pull out of the competition after Japan's Naomi Osaka withdrew after the first round of group matches with a shoulder injury.