Nick's Picks For Day 6

© Getty ImagesRoger Federer, who won the 2005-06 Miami titles, plays wild card Ryan Harrison.

Legendary tennis coach Nick Bollettieri offers his commentary and prediction for three of the hottest matches on Saturday’s schedule.

[3] Roger Federer vs. Ryan Harrison
When you play against Federer, you’re playing against somebody who can do anything with the ball. But I’ve been working with Ryan and I can tell you his kick serve is very heavy and it penetrates. I talked to Potito Starace, who Ryan beat in the first round, and he said the same. So against a one-handed player like Federer, that can really give him a little havoc. The question mark on Ryan has been his composure and he’s made great strides. Before he wasn’t as poised on the court and that zapped his energy and it got the audience against him. But now it seems like he has turned that corner. And I think the new maturity might be enough to make this a close match. But Federer can just do things that no one else can do, so that means Ryan is in for a tough day.

NICK’S PICK: Federer in 3 sets

[2] Maria Sharapova vs. [Q] Sloane Stephens
Sloane is a fantastic natural athlete. She’s still very young but you can tell she’s growing up on the court. Before she was good for a few points, but now she is putting it all together. She qualified to get in the draw here and she held her composure through a rough match on Thursday against the good Italian, Errani. Against Sharapova, Sloane has to just go for it. The problem is that Sharapova is one of the most mentally tough players in the history of the game. And she knows how to come forward and punish with those flat, heavy groundstrokes. Sloane will give everything she’s got, but Sharapova will be all business.

NICK’S PICK: Sharapova in 2 sets

[31] Andy Roddick vs. Gilles Muller
Roddick needs to dictate play if he wants to win this match. Muller is a lefty with a big serve and he’s dangerous. He took out Andy at the US Open a few years ago in the first round. Andy really wants to rack up more wins this year and he knows that he’s going to have the Miami crowd on his side. But he needs to mix up his serve and when he gets into rallies he needs to stay on the damn baseline. He cannot get stuck eight to 10 feet behind the baseline, trying to beat Muller with any of that backhand slice crap—he’ll never have a chance. If he puts all the pressure on Muller with his big serve and hits hard angles to move him around, he has the edge.

NICK’S PICK: Roddick in 3 sets