Rahm topped the Official World Golf Ranking and will head to the Games fresh from becoming the first Spaniard to win the US Open.

He secured his first major on Sunday (June 20), finishing the tournament in San Diego at six-under-par, one shot clear of South Africa's Louis Oosthuizen.

Oosthuizen will not take up his spot in the 60-man Olympic tournament after confirming he had made the "difficult decision" to withdraw.

"Qualifying for the Olympics is a humbling accomplishment and there’s no greater honour than representing your country, so it has been a very difficult decision for me, my team and my family to withdraw from playing in Tokyo," Oosthuizen said.

"I am focused on finishing a strong FedEx Cup season in the States, in addition to honouring family commitments with the new life we are building at the farm.

"Family has always been my core and this is the best decision for us at this time in our lives.

"My best are with the South Africans competing."

Oosthuizen is one of the highest ranked players to miss the Games, joining world number two Dustin Johnson among the absentees.

Johnson, the 2020 Masters champion, announced in March that he would prioritise competing on the PGA Tour.

The United States will field a strong team despite Johnson's absence, with Justin Thomas, Collin Morikawa, Xander Schauffele and Bryson DeChambeau each taking up the opportunity to compete.

DeChambeau is the lowest ranked member of the men’s team at sixth on the standings.

Rory McIlroy will represent Ireland at the Games, with Japan’s reigning Masters champion Hideki Matsuyama set to lead the host nation’s challenge.

McIlroy and Matsuyama were among over 20 absentees from the Rio 2016 golf tournament, which marked the sport’s return to the Olympic programme.

Italy’s Francesco Molinari was another Rio 2016 withdrawal who has taken up their place for Tokyo 2020.

It highlights the increased enthusiasm for the tournament, with only nine players turning down their places.

The men’s tournament has still faced notable withdrawals, with top ranked English player Tyrrell Hatton declining a place in the British team and Spain’s Sergio Garcia also opting against competing at the Games.

Paul Casey and Tommy Fleetwood will represent Britain, while Rafa Cabrera Bello joins Rahm in the Spanish team.

Australia’s Adam Scott had already opted not to receive a place at the Games.

He previously questioned the need for golf to feature at the Olympics.

None of the Rio 2016 medallists will compete, with Britain’s Justin Rose, Sweden’s Henrik Stenson and Matt Kuchar of the United States failing to qualify.

The Tokyo 2020 men’s golf tournament will take place from July 29 to August 1 at the Kasumigaseki Country Club.