Top seed Casper Ruud suffered a shock first-round exit at the Queen's Club Championships, going down in straight sets to British ATP Tour debutant Ryan Peniston in west London.

The French Open runner-up struggled to get going as he fell to a 7-6 (7-4) 7-6 (7-2) defeat to the world number 180, who was backed by a boisterous home crowd throughout.

Ruud struggled from the off as Peniston forced four break points in the Norwegian's first service game, and his miserable outing was rounded off when his opponent raced into a 5-1 lead before serving out a second-set tie-break.

After claiming the scalp of the world number five, Peniston told the BBC: "I can't really believe it. It feels like a dream. It doesn't feel real.

"I think I've been playing well. Casper is an unreal player and he did so well at the French Open, so I knew it was a tough ask. Four or five years ago I was sitting in the crowd just watching so to be here now is just unreal."

Ruud was not the only big name to fall at the first hurdle, with fifth seed Diego Schwartzman going down 6-1 6-4 against big-serving Sam Querrey to become the fourth of the top five seeds to fail to reach the round of 16.

Second seed and defending champion Matteo Berrettini is the exception after faring much better against another home favourite, cruising past Dan Evans 6-3 6-3, while Stan Wawrinka downed Francis Tiafoe 7-6 (7-2) 6-7 (6-8) 7-6 (7-5), and Denis Shapovalov's clash with Tommy Paul was suspended by darkness at one set apiece. 

Elsewhere, world number six Stefanos Tsitsipas progressed through his opening match at the Halle Open, beating Benjamin Bonzi 7-6 (7-1) 1-6 6-3 to set up an enticing last-16 clash with Nick Kyrgios, who bested Daniel Altmaier 6-3 7-5.

Fourth seed Felix Auger-Aliassime also progressed after being taken to three sets, beating Marcos Giron 6-3 5-7 6-3.

Meanwhile, defending champion Ugo Humbert will face a tough round-of-16 match against fifth seed Hubert Hurkacz after the Pole overcame Maxime Cressy 6-4 4-6 6-4.