Novak Djokovic can become the first man since Rod Laver to win the calendar Grand Slam, according to Andre Agassi.
Djokovic, 27, matched Agassi's tally of eight career majors in January, when he won his fifth Australian Open title.
But the American said if Djokovic can replicate another of his feats - completing a career slam - at the French Open, starting May, then the Serbian is poised to take all before him in 2015.
No man has won all four majors in the same year in the Open Era since Australian legend Laver in 1969.
Agassi's wife Steffi Graf (1988) and Margaret Court (1970) are the only women to have achieved the feat in that time.
Standing between Djokovic and a Grand Slam is Rafael Nadal, who has won at Roland Garros in nine of the past 10 years.
"Before he [Djokovic] won Australia I said there's a heck of a chance we're going to see the first time since Laver someone win all of them in the same year," Agassi said.
"I think he's really capable of that.
"He's playing at a level above everybody at the moment.
"I think he still has a lot of room for improvement and if Nadal doesn't get himself right for Paris, [Djokovic can go all the way].
"That [Nadal] will be his [Djokovic's] biggest stumbling block. Getting past him there [at Roland Garros] is no easy task.
"I think he's looking at a pretty dominating year."
Speaking ahead of his native United States taking on Great Britain in a Davis Cup World Group tie starting Friday in Glasgow, Agassi said British number one Andy Murray - who lost to Djokovic in the Australian Open final for a third time in January - will not feel the burden of expectation.
The two teams will meet in the World Group first round for consecutive years, on the back of the British outfit's upset of the Americans in San Diego in 2014.
On that occasion, Murray won both of his singles rubbers to lead Leon Smith's men to victory, and Agassi does not expect the Scot to be affected on home soil at the weekend.
"You have to look at the competitor himself. It seems like it will be an advantage but it's usually not," Agassi said, when asked about the mindset of players competing in home ties.
"But when it comes to Andy, I think he has proven to everybody, certainly to me, that when he has that pressure of playing in the championships at Wimbledon, in front of his home crowd, it makes him a better competitor.
"He doesn't get as distracted or as disappointed out there on court. He doesn't let his bad moments carry on to more.
"He really takes care of business in a way I wish he did all of the time, so I think it's going to help him."