Andy Murray, Stan Wawrinka and Milos Raonic all suffered shock first-round exits at the Aegon Championships as their respective Wimbledon preparations were dealt a damaging blow.

Five-time and defending champion Murray was eliminated in straight sets by world number 90 Jordan Thompson, a lucky loser only given a second chance due to Aljaz Bedene's withdrawal because of a wrist injury.

And an out-of-sorts Murray could not cope with his opponent, Thompson prevailing 7-6 (7-4) 6-2 to leave the world number one contemplating his hopes of retaining the Wimbledon title.

"[It's] a big blow, for sure. This tournament has given me great preparation in the past. When I have done well here, Wimbledon has tended to go pretty well, too. But, if I play like that, I certainly won’t win Wimbledon. I can play better than that," said Murray.

"He played better than me. The first set there was not much in it. I made some mistakes in the middle part of the tie-break, which gifted it to him a little bit.

"That wasn't a great period of the match for me there... I didn't create loads of chances, really. I didn't return particularly well. He served big. He served well."

Thanasi Kokkinakis, meanwhile, was elated after securing what he described as the biggest win of his career by dumping out Raonic, who was a losing finalist at Queen's and Wimbledon last year - both defeats coming against Murray.

Ranked 698th in the world after a litany of shoulder, pectoral and abdominal problems, Kokkinakis saved eight break points in the opening set and rescued three set points in the second before prevailing 7-6 (7-5) 7-6 (10-8).

"It means everything, this match. It's huge for me," said Kokkinakis. "I've been out of the game for so long. I'm trying to look forward now - it's been brutal.

"I'm trying to get myself going week by week. I think it was 22 months out of the game but I can't wait to play my next game."

And on a day of shocks and surprises, world number three and French Open runner-up Wawrinka was beaten 7-6 (7-4) 7-5 by Feliciano Lopez as, like Murray and Raonic, the Swiss was left to contemplate a week on the practice courts.

Fourth seed Marin Cilic is now the highest-ranked player left in the competition, the 2012 champion overcoming John Isner 7-5 6-3.

Nikoloz Basilashvili saved a whopping 11 match points to force a deciding set against Gilles Muller, who required another two in the third to finish a mammoth 6-4 6-7 (17-19) 6-4 victory.

Tuesday's other first-round winners were Julien Benneteau, Viktor Troicki, Jeremy Chardy, Sam Querrey, Daniil Medvedev and Stefan Kozlov, the American teenager ousting Steve Johnson for just his fifth ATP Tour victory.