When we say that Roger Federer’s “worst” surface is clay, it’s like saying that season (fill in the blank) is the “worst” in Mad Men. They are all great, just as Federer is strong on every surface, though his game is best-suited for grass and hard courts.

But while Federer’s offensive abilities are somewhat diminished on slow red clay, other elements of his game are accentuated. Two that we saw today are his footwork and defense, a pair of overlooked qualities that were pivotal in Roger’s rise to the top. They were also the perfect antidotes to Lukas Rosol, who took an early break-of-serve lead in their third-round match at Monte Carlo. When the effects of the medicine began to sink in, Rosol weakened and Federer, who won 6-4, 6-1, looked like the clay-court star that he is.

Rosol’s game is built around landing roundhouse punches; ask Rafael Nadal about that. But there’s a reason why Rosol hasn’t built upon that colossal upset to any significant degree—his high-risk strategy is difficult to consistently execute. It’s even harder to on clay, where more shots and greater patience are required. Add in the fact that Rosol’s opponent danced on the dirt today, tracking balls down while transitioning to offense, and it seemed far-fetched that the Czech would make his 2-1 first-set lead stand.

Rosol kept it all that way to 4-3, but at that point Federer’s superiority burst through like an overflowing dam. The three-time Monte Carlo finalist won the next three games with two breaks, and took nine of the next 10 games overall. Rosol kept swinging, but looked largely immobile, lacking the creativity needed to succeed. That was in sharp contest to Federer, who used the surface to his advantage by building each point until the moment he knew, with a fair amount of certainty, that it was time to strike. That is, if Rosol didn’t hand over the point with an error.

By the time Federer led 4-1 in the second set, Rosol had grown visibly frustrated with the task at hand, particularly after a forehand found the net at 30-all. The clock was ticking, fast, and despite Rosol’s early surge, he didn’t even keep Federer on his “beloved clay” for more than 57 minutes. Federer should expect a longer workday in the quarterfinals, where he’ll face Jo-Wilfried Tsonga.

One final note: Both Federer and Rosol landed 60 percent of their first serves in, but what they did afterward was telling. Federer won a staggering 91 percent of those points; Rosol won barely more than half, at 54 percent. Footwork and defense—as potent as forehands and aces on clay—played large parts in that.