With the fourth round of the US Open in the books, it's time to highlight which players are on the rise and which ones look most vulnerable heading into the next round. Players who have been eliminated are of little interest to fantasy owners as the tournament unfolds, so this column is meant to take a look ahead based on what's happened so far rather than reflect on the past.
Roger Federer - Federer was out of rhythm to start this tournament, but he has looked incredibly sharp in the last two rounds, dropping only five games against Daniel Evans in the third round before losing just four games in a fourth-round rout of David Goffin. With an injured Novak Djokovic (shoulder) falling in his fourth-round encounter with Stan Wawrinka, Federer is the clear favorite to advance to the US Open final for just the second time since 2009. He also owns a 7-0 head-to-head edge against quarterfinal opponent Grigor Dimitrov.
Rafael Nadal - Nadal and Federer are on a collision course to finally meet at the US Open for the first time in their historic careers. Such a meeting could only occur in the final, and both guys are going to be awfully tough outs before then. After cruising early in the tournament, Nadal was finally tested in the Round of 16 by Marin Cilic. He responded beautifully after dropping the second set, coming away with a 6-3, 3-6, 6-1, 6-2 victory. The Spaniard also holds a 7-0 career head-to-head edge against quarterfinal opponent Diego Schwartzman.
Matteo Berrettini - Berrettini has enjoyed his first career run to a Grand Slam quarterfinal, but the big-serving Italian just doesn't seem quite as dangerous as the remaining players left in the draw. His hard-court record coming into this tournament was just 5-9 this year, so Berrettini will be the clear underdog against Gael Monfils in the quarterfinals.
Stan Wawrinka - After landing his latest major victory over Djokovic, Wawrinka is certainly eyeing a fourth career Grand Slam title. He'll likely be the underdog in every match going forward, starting with a quarterfinal against No. 5 seed Daniil Medvedev, but Wawrinka's knack for stepping up on the biggest stage makes him extremely dangerous as the second week unfolds.
Serena Williams - With most of the other big names knocked out, Williams looks like the clear favorite to take home this title. She lost a set to Catherine McNally in the second round and won the second set 6-4 over Petra Martic in Round 4, but Serena has been blowing out the competition otherwise, taking every set by a score of 6-3 or easier. She shouldn't have trouble taking care of No. 18 seed Qiang Wang in her next match, as this is Wang's first career Grand Slam quarterfinal.
Belinda Bencic - Bencic is into her second career US Open quarterfinal thanks to a marquee 7-5, 6-4 win over top seed Naomi Osaka in the Round of 16. The 13th-seeded Bencic is the highest-ranked player left in her half of the draw and will be favored against No. 23 Donna Vekic in the quarters.
Elise Mertens - Mertens has cruised into the quarterfinals without dropping a set, but the No. 25 seed is about to face a drastic increase in difficulty of competition. She's yet to face a seeded opponent and will now have to deal with No. 15 Bianca Andreescu, who should be ranked even better than that. Match-to-match momentum certainly exists in tennis, but don't expect Mertens to carry over her success from the earlier rounds here.
Bianca Andreescu - Andreescu is the greatest obstacle to a Williams-Bencic final, and she won't be much of an underdog should an Andreescu-Bencic semifinal come to fruition. The Canadian teenager already has a pair of hard-court WTA Premier titles this season, and Andreescu could well be a top-five player already if not for a shoulder injury that robbed her of a few months' potential points. If she can hold her nerve while playing in the latter stages of a Grand Slam for the first time, the No. 15 seed could do something special here.