Juan Martin del Potro backs Andy Murray for number one

Juan Martin del Potro has insisted that Andy Murray can become the world number one this year.

The Argentine overcame Murray in the quarter-finals of Indian Wells last week, but he has branded the Australian Open holder "a big champion".

"Murray is a big champion, he already won a Grand Slam, he made the finals in Australia and he has everything he needs to be at the top in the future," Del Potro told reporters at a press conference.

"He will be fighting for the world number one place this year and he can take a big opportunity in the grass season."

Murray is currently ranked number three in the world.