Rory McIlroy is "completing the package" and has never been in a better place mentally according to Graeme McDowell, who sees no reason why his countryman cannot win The Open this week.

Expectations will be high on McIlroy and McDowell from a home support witnessing the event being played at Royal Portrush after a 68-year absence.

Three years ago, speaking prior to the same tournament, McIlroy suggested he would not even watch golf at the Olympics let alone feature, but earlier on Wednesday confessed a fear of regret at not playing at the Games has fuelled a re-think and he intends to compete at Tokyo 2020.

The only complication for McIlroy is seemingly whether to represent Ireland or Great Britain in Japan.

McDowell acknowledged the difficulty McIlroy has with his decision, but says the four-time major winner has never been in a better place mentally as he attempts to lift a second Claret Jug.

"In the whole Olympic question, Northern Ireland sits in such a unique, precarious, kind of situation," he said. 

"There's no right or wrong answer, which is difficult for an athlete, especially one who has such a high profile like Rory.

"[But] as far as the kind of ambassador he is, he's fantastic. He's Ireland's greatest ever player and he's a great role model for kids. 

"To me as he continues to mature I feel like this year, especially, I've never seen him in such a good place mentally. 

"I feel like he's grown up a huge amount and certainly he's embracing the challenges ahead of him as he becomes older. He's certainly a lot more philosophical these days, I feel like. 

"He's done a lot of work on his game, on the mental side of his game and like I say I've never seen him so calculated and in such a good place mentally. 

"Physically we've never doubted him in any way, shape or form. I feel like he's completing the package as we speak. It wouldn't surprise me to see him go real close this week, if not win."

McDowell also reflected on how the decision to bring The Open back to Portrush for the first time since 1951 came to be.

The 39-year-old said initially it started as a joke with former R&A chief Peter Dawson, but when he, Darren Clarke and McIlroy all became major champions the prospect became much more real.

"As a kid I never really thought about [why Portrush did not host The Open]," he added. "I never really thought about the reasons why. 

"I mean, the obvious political struggles that we had, I was too young to really grasp the magnitude and the reasons and be able to comprehend what the solutions were back in those days.

"But when I eventually got out here on Tour and started spending time at Open Championship venues and got familiar enough with Peter Dawson to be able to kind of give him a little bit of a ribbing, it started off as a joke, 'Why can't we go back to Portrush?' Myself and Darren and Rory, especially. And the reasons were: Infrastructure, and this and that and the other.

"When the ball really started to get rolling was when Padraig [Harrington] won his three majors and then I won and Rory and Darren picked up a major each, as well. And the jokes turned kind of serious. 

"It was the Irish Open in 2012 when we broke the European Tour attendance record. I think the R&A couldn't ignore the fact that this could be a commercial success. The jokes became very serious."