Australian Open champion Stanislas Wawrinka said he did not believe he was good enough to win a Grand Slam.
The Swiss, 28, beat world number one Rafael Nadal 6-3 6-2 3-6 6-3 in Sunday's final in Melbourne.
He is the first man outside the 'big four' of Nadal, Roger Federer, Novak Djokovic and Andy Murray to win a major since Juan Martin Del Potro in 2009.
"I never expected to win a Grand Slam because, for me, I was not good enough to beat those guys," said Wawrinka.
It is a measure of Wawrinka's achievement that, along with Del Potro, he is only the second man aside from the 'big four' to win one of the sport's major titles since Marat Safin at the 2005 Australian Open.
"To win a Slam, to be number three [in the rankings], both for me is a big surprise," said Wawrinka. "But I think more so to win a Slam, because in the ranking you can be number three without winning a Slam. But now both are happening, so it's a big surprise.
"It's an amazing feeling. I saw Roger winning so many Grand Slams in the past, so now it's my turn to win one.
"If you look at the 10 past years, except Del Potro, it's only the top four guys who were winning all the Grand Slams."
Wawrinka's success this week takes him past 17-time major winner Federer to become Swiss number one for the first time.
"Roger is a good friend," he said. "He's for me the best player ever. He's been there so many years.
"He was struggling a little bit last year, but he's an amazing player, amazing friend, because he always wants the best for me.
"He's always texting me. Even if he lost, like in the US Open [third round], he was the first person to text me before the match or after the match.
"I didn't call so many people, but my wife, my daughter, my sister, and Roger called me. So, yeah, it was nice for me.
"I know that he's really, really happy for me. He always wanted the best for me."
Wawrinka played superbly to lead by a set and a break in Sunday's final, before the match took a turn when Nadal received treatment for a medical timeout - something Wawrinka quizzed the umpire about.
"I just wanted to know what was the problem of Rafa," he said. "Because before he asked the physio, he was checking his feet. I didn't know really what was the problem.
"Normally when the physio is coming on the court, the umpire always tells the opponent why he's coming. He didn't want to tell me."
After moving two sets up, Wawrinka dropped the third and lost an early lead in the fourth as he struggled to put away an ailing opponent.
"I was surprised how well I started the match," he said. "In the beginning, he was good, he was fit, he wasn't injured. And myself, again, I was playing amazing tennis.
"Then there was the second match in the match. I had to stay calm with myself, just try to stay aggressive, because he was injured.
"But he was still trying a little bit. It was not easy. I started to be really nervous because I started to realise that I could win a Grand Slam.
"So it wasn't easy, but at the end I just came back to the game and focused on what I wanted to do."