US Open ATP Quarter-Finals Round-up | Carlos Alcaraz title defence over in five-set thriller against Ben Shelton as Tiafoe completes comeback versus Michelsen

The first day of ATP quarter-final action was always going to be a dramatic one, but even the most optimistic of tennis fans would not believe what would be in store in day ten of the US Open as USA's Grand Slam hopes took a huge boost.

The main story was always going to come from the Carlos Alcaraz - Ben Shelton showdown. Both players came into this in threatening form, but it would be Alcaraz who succumbed to a very surprising defeat. He will not defend his title in a first Grand Slam loss since the 2025 Wimbledon final as Shelton matches on following a contest that ended at 3:30 in the morning.

In the other match, it looked like Alex Michelsen would already be waiting for him after taking a two-set lead. Nevertheless, Frances Tiafoe is accustomed to the odd five-set thriller and produced an incredible comeback to prevail and reach the semi-final at Flushing Meadows for the third time.

Tiafoe produced one of the most remarkable comebacks of the US Open, recovering from two sets down and a game away from defeat to stun Michelsen in a four-hour, 38-minute thriller. Michelsen looked firmly in control for much of the opening two sets, breaking Tiafoe repeatedly with aggressive baseline tennis and well-timed trips to the net. The 22-year-old took the first set 7-5 and then moved within one set of the semifinals by taking the second 6-3.

Tiafoe's comeback began when Michelsen served for the match at 5-4 in the third set. For the first time all night, the pressure appeared to get to the younger American, who committed two crucial double faults as Tiafoe broke back. From there, the momentum swung dramatically. Tiafoe won 17 of the final 22 points of the set, closing it out 7-5 with a forehand winner that sent Arthur Ashe Stadium into a frenzy. He then carried that energy into the fourth, taking control of the rallies and forcing Michelsen to play increasingly under pressure as he levelled the match 6-3.

Even after that turnaround, Michelsen refused to disappear. He opened the deciding set by winning the first three games, putting Tiafoe back on the brink, but the 11th seed again found a response and broke in the fifth game to get the set back on serve. Neither player could create separation after that, sending the match into a deciding tiebreak. Tiafoe finally made the difference there, securing the decisive mini-break at 3-2 and never trailing again before closing out the 7-6(6) victory.

The victory sends Tiafoe to his third US Open semifinal, all of them coming in the last five years, and makes him only the second American man after Andre Agassi this century to reach three semifinals in New York. For Michelsen, it was a heartbreaking end to his deepest Grand Slam run, but the match ended with one of the tournament's most emotional moments as Tiafoe immediately embraced his fellow American, who was left in tears after the defeat.

The opening set was closely contested from the start, with both players holding serve confidently and neither facing any real danger on return. They traded holds throughout the early stages and arrived at 5-5 with little to separate them. Alcaraz finally created the first opening, breaking to move ahead and put himself in position to serve for the set, but Shelton immediately responded with a break to love.

The Spaniard had let his opportunity slip away, but he showed greater composure in the tiebreak. After falling 3-5 behind, Alcaraz raised his level at the crucial moment, winning four points in a row to take the opening set. It was a set that Shelton had done enough to win, but Alcaraz's ability to find another level under pressure allowed him to escape with the lead.

The second set, however, swung firmly in the American's direction. Alcaraz was immediately forced to fight on serve, saving four break points in the opening game, an early warning of what was to come. Shelton then had to save three break points himself in the following game, but after surviving that scare, the ninth seed took control. He won three consecutive breaks, repeatedly exposing an increasingly erratic Alcaraz and capitalising on a significant drop in the Spaniard's level. Shelton's three straight breaks gave him a comfortable 6-1 set and completely changed the complexion of the match.

Following that, Shelton stamped his authority on the match with an early break in the third, showcasing his ruthless nature on court and giving Alcaraz something else to think about. Alcaraz was starting to get in trouble and Shelton looked to capitalise. The reigning champion had chances to break straight back and halt the momentum of his opponent but failed to convert them. His next chance came right at the end of the set, but Shelton stayed firm and sunk a first set point to lead in this enthralling battle.

The tables turned in the fourth set. Similar to the second, it was a commanding 6-1 scoreline, but it went the other way as Alcaraz desperately sought a way back into the match. He did so with great effect. He was forced to defend break points in the first game but then took control with an ominous break. Shelton got on the board but Alcaraz was in a rampant mood. Another break of serve sealed a 5-1 lead before an eye-catching hold to love got him back on parity.

The fifth set was always going to be packed with drama, and in this instance it was brewing right until the very end. It was getting late in New York with the players still managing to put in a huge amount of effort to still compete at the highest level. Alcaraz missed a break point to lead 4-2 before Shelton's golden opportunity came and went. Three chances to lead and serve it out were wasted as Alcaraz breathed a huge sigh of relief. A super tiebreak was called into action as the match passed the four hour mark. It was tight all the way through it with Alcaraz leading at 6-5. However, from that point onwards the match was only ever going in one direction. The American No.1 dropped just one point as he made a late dash for home. He won the tiebreak 10-7 and confirms not just a first win over Alcaraz, but a second semi-final at Flushing Meadows in one of the biggest wins of his life.