Former world number one Rory McIlroy says winning on the PGA Tour is harder than ever as he prepares to launch his 2021-2022 season at the CJ Cup in Las Vegas on Thursday.

McIlroy is chasing his second title of the year at this week's tournament in Nevada, where the CJ Cup relocated to from its normal home on Jeju Island in South Korea last year due to the pandemic.

McIlroy snapped the longest winless streak of his career with victory at the Wells Fargo Championship at Quail Hollow in May, ending an 18-month drought which followed a dazzling 2019 that included four victories.

The 32-year-old four-time major champion said Wednesday he believes seasons featuring multiple titles are going to be increasingly harder to come by, reflecting the depth of talent on the tour.

"You turn up to a PGA TOUR event where there's 144, 156 players and, you know, you feel like three-quarters of the field have a chance to win and that just sort of illustrates how deep the fields are," McIlroy said.

"It's tough to win, right? I've had a couple of seasons where I've won four and five times and I think nowadays that's an achievement."

Ben Hogan retains the all-time record for wins in a single season, snagging 13 titles in 1946. More recently, Vijay Singh and Tiger Woods both won nine titles in a single season in 2004 and 2000 respectively.

McIlroy believes those kind of achievements may not be repeated.

"The seasons like Vijay and Tiger ... I may be wrong, but I don't know if we're going to see them again," McIlroy said.

"I think a really good season nowadays -- three wins is exceptional, two wins is very good, and then anything like above three, you're the best player in the world at that point."

McIlroy meanwhile will tee it up this week after a disappointing Ryder Cup campaign which saw him win just one point as Europe were thrashed by the US team by a 10-point margin.

An emotional McIlroy wept as he reflected on his performances in the immediate aftermath of that defeat at Whistling Straits.

McIlroy admitted on Wednesday he had been surprised at his tearful reaction to the loss.

"I don't necessarily get that emotional about golf, so I guess in that way it surprised me," McIlroy said. "It's a very emotionally charged week.

"But I think it was a good thing for me. I think I may be realized a couple of things about myself that maybe I had known but I was maybe trying to keep down and not let them out.

"I was surprised at how emotional I got, but then after a little bit of reflection over the last couple of weeks, I sort of realized why I did get that way."