The rumbling of Ivo Karlovic's size 16 sneakers grew louder, but Roger Federer was too busy bending a sharp-angled forehand pass by the lunging big man to take much notice.

Some players rush the net, Karlovic can suffocate it, but even Ivo paused to watch a replay of Federer's snazzy pass as if seeking visual confirmation of an optical illusion. Federer won plenty of style points — and converted the lone break in the opening game — in a sharp 6-4, 7-6 (4) dissection to reach the Miami third round.

The match pitted two of only six ATP players to hit more than 8,000 aces. The Federer serve was the key stroke: He served 75 percent, issued nine love holds, did not face a break point and dropped only three points on serve.

The tallest man in tennis was facing several high hurdles today: Federer had won 10 of their prior 11 meetings, the Croatian's game had wilted with just two wins in nine prior Crandon Park appearances, he struggles to keep pace with the faster Swiss in running rallies and his slice backhand has held up to Federer's forehand about as well as a broom in a joust.

Chip and charging in the opening game, Federer blocked a stretch forehand volley down the line eliciting an errant backhand volley for break point.  Signs of stress erupted into a full crack when Karlovic spun a second serve into net to drop serve. Federer quickly backed up the break with a love hold for 2-0. The fifth-seeded Swiss zapped an ace down the middle, sealing his second love hold for a 3-1 advantage after just 11 minutes of play. Given the fact Karlovic ranks 84th on the ATP in return  games won this season (10 percent), an early break can be fatal for the big man, who never made inroads on Federer's serve.

Cruising through most service games in about a minute's time (TennisTV.com stats showed he averaged 76 seconds per hold), Federer opened with four consecutive love holds and came within a point of a perfect serving set before missing an inside-out forehand wide. Dancing around his backhand, he lashed the same shot for a winner on the next point, sweeping the 29-minute set with a firm "Allez!" while winning 20 of 21 points played on his serve.

The 6'11" Karlovic can be such an imposing presence at net, squeezing a passing shot beyond his wide wing span can look as arduous as leaping a telephone pole. Ivo made a pair of terrific lunging backhand volleys to open the seventh game of the second set, eventually holding for 4-3. Karlovic is an unsettling adversary because he can detonate points with one swing of his wrecking ball serve, denying opponents any rhythm in rallies — or even obliterating the opportunity of a rally.

The quandary Karlovic faces against the 17-time Grand Slam champion is clear: He can't hang around the baseline for long and venturing forward often found him lunging after Federer's whip-lash forehand or stooping low to scrape volleys off a slithering backhand slice.  Karlovic, whose backhand volley is sounder than his forehand, fought off a pair of break points to hold for 5-4, but would win just one point on Federer's serve the rest of the way.

On the first point of the tiebreaker, Karlovic conceded the mini break pushing a forehand volley long. Another Karlovic forehand volley floated beyond the baseline as Federer built a 3-1 lead before closing a clean 74-minute victory with 27 winners against six unforced errors.