Del Potro beat world number one Roger Federer in an intense final at Indian Wells on Monday (AEDT) to add to his Acapulco title.

The Argentine is the fifth seed in Miami and gets under way against Robin Haase, with Novak Djokovic potentially awaiting in the fourth round.

Del Potro, though, feels his recent successes have been taking a toll on his body.

"I'm not thinking too much about the slams," Del Potro told reporters on Wednesday. "I'm just enjoying the moment. I know what I have been through to get this time and this place and this ranking.

"I am still calm, you know. I came here to play another tournament. It will be my fourth tournament in a row.

"I'm tired. And mentally and physically it's not easy to deal with all of these emotions."

Del Potro's strong form has seen the 29-year-old climb to sixth in the world rankings.

But despite being only 750 points behind world number three Marin Cilic, Del Potro says he is not motivated by his position.

"I always say the ranking number doesn't change or doesn't mean too much to me," he said. "I was number 1000 a few years ago - and now I'm number six. 

"I have good chances to keep growing, growing up, but I'm not thinking about that."