Britain's Jack Draper marked his debut in the world's top 100 with a first win over a top-20 ranked opponent when he beat Taylor Fritz at Queen's.
Draper, 20, used his powerful game to good effect on the grass, leading to a 6-3 6-2 victory on the opening day of the Cinch Championships in west London.
American fourth seed Fritz is ranked 14th in the world, but was overwhelmed by British number four Draper.
British number one Cameron Norrie lost to Grigor Dimitrov in the first round.
Norrie, seeded third, was looking to go one better than last year's run to the final, where he was beaten by Italy's Matteo Berrettini.
The world number 11 edged a tight first set by dominating the tie-break against Bulgaria's Dimitrov, but the 2014 champion fought back to win 6-7 (2-7) 6-1 6-4.
Two career milestones on same day leaves Draper feeling 'proud'
Draper, who moved up to 99th in the world on Monday, missed the French Open with a minor muscle injury as he prioritised the grass-court season.
Against Fritz, Draper looked strong as he marked his return to Queen's - where he reached the quarter-finals last year - with a confident victory.
"I'm very proud of myself, I have done a lot of work, I have known for a while my level has been good enough to compete at the highest level," he said.
"But there is one thing saying it and one thing getting wins at this level against players like Taylor.
"So I'm really happy and it gives me a lot of confidence."
Draper played with confidence and conviction, particularly on serve, saving all three break points and winning 91% of his first-serve points.
While he was unable to take a first match point on Fritz's serve, Draper completed the win when he hit a second-serve ace to the jubilation of the home crowd.
Afterwards, Draper described the win in front of about 9,000 fans as "amazing".
"At the start of my career I had not played in front of as many people as this, the nerves are still there but I'm glad the way I played," said Draper, who plays a qualifier in either France's Quentin Halys or Finland's Emil Ruusuvuori next.
Draper is one of seven British players in the main draw at Queen's, although Andy Murray's participation remains in doubt after the Scot picked up an injury in the Stuttgart final on Sunday.
Former world number one Murray, a five-time singles champion at Queen's, is set to have a scan on Monday to reveal the extent of an abdominal issue.
In Monday's final singles match, British number five Liam Broady takes on Croatia's Marin Cilic - the 2017 Wimbledon runner-up who reached the French Open semi-finals earlier this month.