Former coach of Andre Agassi, Darren Cahill believes Nick Kyrgios can match anyone in the world, despite not having a coach.

The 21-year-old has won three ATP titles and is currently a world number 13 – all of which he achieved without a coach. While Kyrgios's talent is undeniable, he is prone to controversy, which may set him back in his quest to be world number one.

Kyrgios previously mentioned he does not love the game of tennis while he was suspended for eight weeks following the 2016 Shanghai Masters for "conduct contrary to the integrity of the game."

In the 2017 Australian Open, Kyrgios crashed out in the second round to Andreas Seppi despite a two set lead, where the Australian committed two code violations, including a point penalty. Following his exit, the youngster admitted that he may need a mentor.

Former world number one, Lleyton Hewitt recently revealed Kyrgios was speaking to one or two guys to become his potential coach.

Cahill – a former coach of Hewitt's – however, believes no coach is necessary for the 21-year-old to reach the top.

"It sounds like he's starting to search for a coach, that would be a good thing if he's a ready to take one on, but if not his game is not in a bad spot, his game is great really," Cahill said as quoted on Brisbane Times.

"We've seen his talent and when he's a fit and healthy and mentally strong he can match it with anyone in the world.

"With Nick it sounds like he's making some good decisions, he's taken on a strength and conditioning trainer but it's going to take some time."

Cahill conceded that Kyrgios won't become world number one overnight but believes if he is fully committed, he will benefit.

"Part of the reason we don't see a lot of the teenagers breaking through and winning majors anymore is because the game has become a lot more physical, which Nick is starting to invest," he said.

"But it doesn't happen in six months, it takes two or three years of consistent work and if Nick commits he will get great benefits out it.

"At the moment I think be patient with him and over the next two or three years, if he does the work off the court we'll definitely see more consistent results from him," he said.