Sam Querrey-Marin Cilic is intriguing, but can anybody stop Roger Federer?

Sam Querrey did not exactly rush from Centre Court after his shock upset of top Wimbledon seed Andy Murray screaming, "Get me Federer!" But a final between them would be a refreshing change of pace. It also would be a well-earned sop for long frustrated U.S. tennis fans.

Federer is the last member of the Big Four standing at All England. Querrey at the moment isn't even part of a Big 25 (he's ranked No. 28). He's also the only semifinalist who's never entered the magical kingdom of a Grand Slam final. Marin Cilic, Querrey's next opponent, is a former US Open champion. Tomas Berdych, Federer's semifinal opponent, had his heart broken on Centre Court in the 2010 final by Rafael Nadal.

The surprise semifinalist Querrey has his work cut out if he hopes to appear in the championship match. Cilic has won all four of their previous matches, three of them on grass. Their third round, overtime epic at Wimbledon in 2012 is the second-longest match in Wimbledon history.

Querrey's motivation is simple: payback. Cilic's three grass-court wins (the other two were at Queens and at Wimbledon in 2009) were all bitter, heavyweight slugfests between 6-foot-6 ace-makers that went the distance -- and more. All of them could have gone the other way, not least because the men have similar games, anchored by massive serves.

Cilic is slightly more mobile than Querrey. He has also seemed fitter and fundamentally stronger. But the American isn't as ungainly as his posture suggests, he has better touch and he would probably edge Cilic out in a serving contest. Querrey has been involved in some long matches this fortnight, so fatigue may become an issue if they stage their usual lengthy brawl. While Cilic has had easier wins, Querrey is battle-hardened. This is really a pick 'em.

Federer's road to the final looks straight and true, but even he can't afford to drive with his eyes closed. This has been a Wimbledon so full of surprises, on both sides of the draw, that an upset of Federer in the semis or final is plausible.

Federer has squinted down at the mug of a fellow Big Four member in his past seven Grand Slam finals. But his last semifinal encounter with an interloper didn't end all that well, and scar tissue hasn't formed over that wound yet. Milos Raonic upset Federer in the Wimbledon semis last July, unleashing the chain of events that -- ironically -- has Federer playing the best tennis of perhaps his entire life.

The immediate obstacle between Federer and a 19th Grand Slam singles title is a familiar one: Tomas Berdych. This is business as usual, because Berdych has been a reliable semifinal punching bag for the Big Four. He's been good enough to make multiple Grand Slam semis on every surface, if not quite mentally strong enough to clear the hurdle but once.

But the one time Berdych made the final, he had eliminated Federer in the quarterfinals of Wimbledon in 2010. Lightning doesn't strike in the same place twice, but then this isn't the same thunderstorm.

Berdych, a 31-year old Czech, hasn't learned any new tricks. He's still a big serve-big forehand kind of guy. But this year he found himself having to fight for his place in the elite top 10 for the first time in more than seven years (he entered Wimbledon at No. 15). Embracing the current trend toward 30-something revivals, Berdych again looks like top-10 material.

While Berdych's ace count is surprisingly low (he's averaging 10 per match) at Wimbledon, he's hit his spots well and won roughly 90 percent of his first-serve points. His first-serve conversion rate is a disappointing 63 percent for the tournament, but his second serve has been outstanding. He's won more than 58 percent of his second-serve points.

That ought to keep Federer on his toes. Berdych has the artillery and solid groundstrokes to impose himself on anyone, although these days nobody would mistake Federer for just anyone.