LONDON — Top seed Stefanos Tsitsipas survived a day of shocks at the Queen's Club grasscourt championships as he claimed two victories on Thursday to reach the quarterfinals.

First the Greek 20-year-old returned to court to complete his weather-delayed first-round clash with Britain's Kyle Edmund before scraping past Frenchman Jeremy Chardy.

Chardy served for the match in the second set but world number six Tsitsipas hung in to level before sealing a 4-6, 7-6(7-0), 7-6(7-4) victory to prolong his debut appearance at the prestigious Wimbledon warm-up event.

"I didn't play very well but I found my returns when he was serving for the match at 5-4," Tsitsipas, being tipped as the most likely of the next generation to challenge at Wimbledon, told reporters. "I didn't play my best, but survived."

Defending champion Marin Cilic, seeded five, was earlier cut down to size by Argentine Diego Schwartzman in the second round, the big-serving Croat slumping to a 6-4, 6-4 defeat.

The result was all the more surprising as it was only the diminutive Schwartzman's third career victory on grass.

Second seed Kevin Anderson, runner-up at Wimbledon last year, went down 6-1, 4-6, 6-4 to Gilles Simon while another Frenchman, Nicolas Mahut, put paid to the hopes of three-times Grand Slam champion Stan Wawrinka.

Mahut won 3-6, 7-5, 7-6(7-2) but there was an awkward moment for the veteran Frenchman as he was given a code violation for unsportsmanlike conduct after leaving a ballgirl in tears when he struck her with a ball.

The qualifier, ranked down at 191 but always a threat on grass, had just dropped serve early on and decided to send down a practice delivery that clipped the ballgirl in the head as she went about her duties at the back of the court.

It was clearly accidental but followed another Mahut incident two days ago when he skidded over chasing a wide ball and ploughed into another unfortunate ballgirl. Mahut and Simon meet for a place in the semifinals.

Tsitsipas belatedly moved through to the second round as he finished off Edmund 6-3, 7-5 having come off the previous night at 3-3 in the second set. He needed seven match points to end home interest in the singles draw.

It took him two hours and 38 minutes to get past Chardy but he says the overtime will stand him in good stead for the challenges ahead, starting with Canada's Felix Auger Aliassime in what looks like an eye-catching quarterfinal.

Auger Aliassime beat Nick Kyrgios 6-7, 7-6, 7-5 in what was the second match of the day for both players.

Kyrgios, who appeared to be going through the motions in the last two games against the teenaged Canadian, was given a warning for smacking a ball out of the stadium.

Earlier, the controversial Australian had also been warned for unsportsmanlike conduct during a straight-sets defeat of Spain's Roberto Carballes Baena in which he accused a line judge of "rigging" his matches and branded the match officials a disgrace. — Reuters