Jon Rahm wiped away a tear of joy after replacing Rory McIlroy as world number one by winning the Memorial Tournament.
A three-over-par 75 was enough to win on nine under, three clear of American Ryan Palmer (74), with Matt Fitzpatrick (68) third on five under, with fellow Englishman Matt Wallace (72) one back.
Rahm is the second Spaniard, after Seve Ballesteros, to top the rankings.
“I’ve accomplished a lifelong goal and any time I can join Spanish history with Seve is incredible,” said Rahm.
“But it’s hard to process right now because golf feels secondary. I lost two family members in the [coronavirus] quarantine.
“There are so many things going through my mind right now that have nothing to do with golf.”
This was the sixth PGA Tour event since professional golf resumed in the United States after an enforced three-month shutdown and had been been earmarked as the first to allow fans in to watch.
However, last week the PGA Tour said the remaining nine events of this season would take place behind closed doors as cases of coronavirus continue to soar in the country.
Rahm, 25, started the final round at Muirfield Village in Ohio with a four-shot lead over Palmer and Tony Finau.
That lead was eight by the eighth hole. “And then it got a little twisted,” said Rahm.
He bogeyed the 10th and then slammed his driver into the ground in anger after hitting his tee shot on the par-five 11th into water. He would double bogey the hole and see his lead cut to five.
It was four when Palmer birdied the short 12th and three after Rahm bogeyed the 14th.
He also looked in trouble on the par-three 16th after his errant tee shot flew into the greenside rough, but he hit a beautifully delicate chip that rolled right into the centre of the cup for a birdie.
“It was an unbelievable shot,” said Rahm. “It was the best short-game shot I’ve ever hit.”
However, in addressing the ball before his chip, television pictures showed that he inadvertently moved his ball a fraction. PGA Tour rules officials studied the footage while Rahm played his final two holes.
He only learned of his potential infringement when being interviewed immediately after his round and before he had signed his scorecard.
“I did not see or feel anything,” he said. “If it did move I did not see anything. It’s not going to take anything away from that shot.
“For that to go in, that was exactly what I needed.”
He was eventually penalised two shots but that only changed the size of his victory.
Fitzpatrick’s 68 was the lowest round of a day when the average score was closer to 76, and moved him 15 places up the leaderboard.
“It was just a grind,” he said after an excellent round which featured one bogey and five birdies and was interrupted by a 50-minute delay as a storm blew across the course.
“Pars were a good score,” he added.
Wallace had three birdies in his final four holes, including one at the last to card a level-par 72 and take joint fourth with Australian Jason Day.
Northern Ireland’s McIlroy had an early birdie but a triple-bogey eight on the par-five fifth hole derailed his round as his reign as world number one finished with a six-over 78 and four over total.
Tiger Woods said he would take “a lot of positives” away from his first tournament in five months despite finishing with a four-over 76 and six over par total.
The record five-times winner of this Jack Nicklaus-hosted event holed birdie putts of 18 and 22 feet on the 16th and 17th holes but he also had five bogeys and a double bogey.
Record 18-time major winner Nicklaus said during the round that he and his wife Barbara both tested positive for coronavirus in March.
The American said his wife had no symptoms, while he dealt with a sore throat and cough for more than a month.
“It didn’t last very long, and we were very, very fortunate, very lucky,” said Nicklaus, who noted that he and his wife, both 80, are at an “at-risk age” for more serious Covid-19 symptoms.
“Our hearts go out to the people who did lose their lives and their families. We were just a couple of the lucky ones,” he added.