World number two Andy Murray believes he is "not that far" from taking Roger Federer's number one ranking.
Fresh from his victory in the Montreal Masters, the 22-year-old said a couple of key defeats were the difference.
"If I had had a slightly better run at the Australian Open or [not lost] a tight one to Andy Roddick at Wimbledon then, who knows?" Murray said
Murray is the defending champion at the Cincinnati Masters where he faces Nicolas Almagro in the second round.
The Scot, who is due to start his campaign on Wednesday against world number 33 Almagro, added that he was not under extra pressure to defend the title ahead of the US Open.
"I would hope I would still be reasonably fresh," he said. "I think it's more mentally than physically that's important, because physically I think I'll be strong enough to compete in the Slam."
Although Murray's victory in Montreal saw him lift his fourth senior Masters title, he is yet to win a Grand Slam - something Federer, who beat Murray in last year's US Open final, has achieved 15 times.
Murray insists, however, that he has been consistent enough this year to deserve his position in the rankings.
"It's not that far. It's a matter of a couple of the matches," he said. "I know it's a long way from losing the semi finals [at Wimbledon] to winning but that would have made a huge difference.
"I would be very close to Roger in the rankings if I had won those two matches from the semis onwards.
"That's really the only difference - getting a Slam - between being number one and two. The other tournaments has been pretty similar."
He added: "Federer, I think, won his first Slam when he played his 17th Slam. I think I've only played 15.
"At 22 I'm still pretty young. I'd love to win a Slam, that's obviously one of my biggest goals, but to say that I'd be disappointed to not win one with the level of competition that's around now is a little bit disrespectful to the players.
"You've got some of best ever playing right now."
Fresh from his victory in the Montreal Masters, the 22-year-old said a couple of key defeats were the difference.
"If I had had a slightly better run at the Australian Open or [not lost] a tight one to Andy Roddick at Wimbledon then, who knows?" Murray said
Murray is the defending champion at the Cincinnati Masters where he faces Nicolas Almagro in the second round.
The Scot, who is due to start his campaign on Wednesday against world number 33 Almagro, added that he was not under extra pressure to defend the title ahead of the US Open.
"I would hope I would still be reasonably fresh," he said. "I think it's more mentally than physically that's important, because physically I think I'll be strong enough to compete in the Slam."
Although Murray's victory in Montreal saw him lift his fourth senior Masters title, he is yet to win a Grand Slam - something Federer, who beat Murray in last year's US Open final, has achieved 15 times.
Murray insists, however, that he has been consistent enough this year to deserve his position in the rankings.
"It's not that far. It's a matter of a couple of the matches," he said. "I know it's a long way from losing the semi finals [at Wimbledon] to winning but that would have made a huge difference.
"I would be very close to Roger in the rankings if I had won those two matches from the semis onwards.
"That's really the only difference - getting a Slam - between being number one and two. The other tournaments has been pretty similar."
He added: "Federer, I think, won his first Slam when he played his 17th Slam. I think I've only played 15.
"At 22 I'm still pretty young. I'd love to win a Slam, that's obviously one of my biggest goals, but to say that I'd be disappointed to not win one with the level of competition that's around now is a little bit disrespectful to the players.
"You've got some of best ever playing right now."