ROME, Italy (AFP) — Brooks Koepka on Wednesday told any fellow LIV Golf players upset at their exclusion from the USA's Ryder Cup team that they need to up their games if they want a spot in future tournaments.

Koepka is the only golfer from the Saudi Arabia-backed tour to play at this week's event in Rome after being selected by American captain Zach Johnson, the five-time major winner only just missing out on automatic qualification despite defecting from the PGA Tour last year.

Earlier this month, Dustin Johnson, who won all five of his matches in the Americans' 19-9 thrashing of Europe two years ago, said his decision to leave for LIV cost him a place on Zach Johnson's team.

But asked by reporters at the Marco Simone course whether Dustin Johnson and other LIV golfers had been treated unfairly, Koepka said: "I don't make the decisions."

"Everybody had an opportunity to get there. I mean, I had the same opportunity as every other LIV player, and I'm here. Play better. That's always the answer."

Koepka said that he is not in Italy to represent other players on the LIV tour, which has also removed European Ryder Cup icons Lee Westwood, Sergio Garcia and Ian Poulter from the equation.

Earlier, Rory McIlroy, the most experienced Ryder Cup player at this year's edition, said that trio would be missing the Europe team more than the Europe team would miss them.

"I feel like I'm representing the USA. That's what I've got on the front of my hat this week, so that's what I'm representing," Koepka said.

"We're just all one team, and that's the way we think. That's what I believe, and I'm pretty sure everybody else there thinks that."

A third PGA Championship win back in May and joint second at this year's Masters the previous month went a long way to convincing Johnson to pick Koepka.

The 33-year-old's record in golf's biggest tournaments gave him a chance of being picked, but it wasn't until his display at the Masters that he had his eye on a spot on the team.