While the final may have been relatively straightforward, matches in the second week of the ATP draw at the US Open still offered plenty of drama. Here are five of the highlights.

5) Semifinals: Marin Cilic d. Roger Federer 6-3 6-4 6-4

Cilic was simply at peak level here, and he put up a dazzling performance against the world No. 3, denying him a chance at his 18th major. Federer was a heavy favorite, but Cilic did not play like it, bombing 13 aces and ripping 43 winners against a shell-shocked Federer.

Cilic took the ball in an aggressive fashion, using the inside-out forehand as a very effective weapon, and he won 87% of his first-serve points. Federer broke just one time, compared to four breaks for Cilic, including an immediate break back when Federer threatened to make it a match early in the third set. The Croat was cool and composed even with a hostile Arthur Ashe Stadium crowd cheering on his double faults. In the final game, Cilic stepped to the baseline and hit three consecutive aces and then quickly seized his first match point to seal his spot in the final.

Federer simply admitted he had been overmatched in this semifinal, and it was a shocking sight to see. Federer, normally a good mover on court, was left scrambling behind the baseline while the lanky Cilic moved fluidly, converting 60% of his net point chances, Additional poise under pressure was shown with his early breaks in both the first and second sets.

4) Quarterfinals: Kei Nishikori d. Stan Wawrinka 3-6 7-5 7-6(7) 6-7(5) 6-4

Nishikori recovered from a grueling late-night five-setter to defeat Wawrinka in a minor upset in the quarterfinals. The man from Japan survived an 18-ace, 68-winner barrage from the Swiss, and his clean, concise strokes did the trick here. Wawrinka was strong on serve, and both players saved a large majority of the break points they faced. Wawrinka also won more total points in the match, but clutch play in the second set, the third-set tiebreak, and late in the fifth set won the day for the top Japanese player in the game.

Nishikori went to net nearly three times as much as Wawrinka did, and he just had the one additional break of serve, perhaps proving that aggressive play is still a key to success in the men’s game.

3) R4: Marin Cilic d. Gilles Simon 5-7 7-6(3) 6-4 3-6 6-4

Gilles Simon always tends to play, and eventually often lose, very grueling five-set matches in Grand Slams, and this match was no exception. The Frenchman gave the eventual US Open champion Cilic his toughest test of the tournament, but even after winning the fourth set he ended up overpowered in the best-of-five format. Cilic posted 23 aces, won 81% of his first-serve points, and smacked a tremendous 70 winners. Simon is a good baseliner, and he battles hard, but he didn’t have enough weapons to truly damage the Croat in this one.

2) R4: Kei Nishikori d. Milos Raonic 4-6 7-6(4) 6-7(6) 7-5 6-4

This was a heartbreaking loss for the Canadian No. 1 Raonic, who has to be thinking about what this tournament could have been for him after all that transpired in the second week. Milos probably should have won this match, but he failed to do so even after hitting 35 aces and winning 82% of his first-serve points. Nishikori earned a boatload of break points, but Raonic saved a vast majority of them, and of the five breaks that Nishikori earned in the match, four of them were countered by Raonic, often in the next game. Nishikori had serious trouble serving sets out and consolidating breaks in this match, even though Raonic is not exactly a challenging returner, and he looked to be wilting in both the third and fifth sets, only to find his second wind and plow through. Raonic piled up errors in this late-night affair, while Nishikori played a much cleaner match. That perhaps was the winning difference.

1) Quarterfinals: Roger Federer d. Gael Monfils 4-6 3-6 6-4 7-5 6-2

In an incredible match, Monfils and Federer gave the crowd and TV audience just about everything they could have hoped for. Monfils played spectacular tennis, firing on all cylinders for nearly four sets, but he wilted under pressure and that was his undoing. Up two sets to one, and at 5-4 in the fourth set, Monfils had two match points. But they were both saved by Federer, and he would go on a roll from there, winning the next three games to take the fourth set and then steamrolling an already mentally defeated Monfils in the fifth set. Federer would go on to eventually lose in the semifinals, as discussed, but at the time he deserved much credit for keeping his Grand Slam hopes alive and clawing back from match point down. The key for him was that Monfils did not serve well when it mattered most and ultimately lost focus too much to win it.