PGA Tour commissioner Jay Monahan described the LIV Golf Invitational as a "series of exhibition matches" while defending his decision to suspend players who defected to the breakaway series.

Charl Schwartzel, who won the inaugural LIV event near London this weekend, has been suspended from the PGA Tour along with the likes of Dustin Johnson, Phil Mickelson and Sergio Garcia for their involvement in the series.

The LIV series is set to hold eight 54-hole, no-cut tournaments with 48-man fields this year, with players not only earning significantly higher prize money, but taking substantial sign-on fees. Bryson DeChambeau and Patrick Reed have been the latest to defect.

Asked why golfers cannot compete on both tours, Monahan took an assertive stance.

"Why do they need us so badly? Those players have chosen to sign multi-year, lucrative contracts to play in a series of exhibition matches against the same players over and over again," he said on CBS' broadcast of the Canadian Open.

"You look at that versus what we see here today, and that's why they need us so badly.

"You've got true, pure competition, the best players in the world here at the RBC Canadian Open, with millions of fans watching. And in this game, it's true and pure competition that creates the profiles and presences of the world's greatest players."

Monahan was particularly critical of LIV's source of investment, with the Public Investment Fund in Saudi Arabia which has been accused of sports washing and using the tour to take attention away from a history of human rights abuses.

He also said players who defected would "have to be living under a rock" to not consider that context, but chose instead to relate the significant outlay to sign players and hold events to the potential return on investment.

"It’s not an issue for me, because I don’t work for the Saudi Arabian government," Monahan said. "But it probably is an issue for players who chose to go and take that money. I think you have to ask yourself the question, why?

"Why is this group spending so much money — billions of dollars — recruiting players and chasing a concept with no possibility of a return? At the same time, there’s been a lot of questions, a lot of comments, about the growth of the game. And I ask, how is this good for the game?

"I would ask any player that has left, or any player that would consider leaving, have you ever had to apologise for being a member of the PGA Tour?"