Two hours into a high-class battle in the fourth round of the US Open on Monday evening, the second set of the duel between Jannik Sinner and Tommy Paul was still undecided. After the crushing blow of conceding an extremely close first set, Paul fought back admirably and forced a second tiebreak with a series of brave shots and confident forays to the net. The 14th seed took a 5-4 lead and was just two points away from leveling the match at 1-1.

The decisive points are where the best players in the world so often pull away from the rest, and at Arthur Ashe Stadium, they were the difference between the two. After Paul missed two consecutive backhand returns on his second serve at 5-4 in the tiebreak, Sinner took advantage of the first set point without hesitation, holing a brilliant forehand return to give him a two-set lead.

Sinner was able to pull away at all decisive moments and showed a performance worthy of a world number one, moving into the quarterfinals with a 7:6 (3), 7:6 (5), 6:1 victory over Paul.

“I also always get more excited when I play important points, important moments,” Sinner said of his decisive match. “In my opinion, that’s what we train for. That’s why you do repetitions on the practice courts, and then you feel more confident, you may have to change a few things to surprise him. You have to serve a little more intelligently. In the tiebreak of the second set, I didn’t serve very well, but I’m trying to find a solution somehow.”

In a draw that has been wide open since early upset wins over second and third seeds Novak Djokovic and Carlos Alcaraz, Sinner underlined his position as favorite to win his second Grand Slam title of the year. But this draw is extremely one-sided. The Italian will next face the only other Grand Slam champion in the draw, Daniil Medvedev, who is also the only remaining former US Open champion. Medvedev was in commanding form on Monday, rolling over Nuno Borges 6-1, 6-1, 6-3.

This year, Sinner has played with a consistency that no male player other than Djokovic, Rafael Nadal, Roger Federer and Andy Murray has matched in recent years. Sinner’s record in 2024 is now 52-5 (91%) and 32-2 (94%) on hard courts. According to Opta, he is the second-youngest player in history to reach the quarterfinals in each of his first 12 tournaments of the year.

This latest success comes two weeks after Sinner and the International Tennis Integrity Agency (ITIA) announced that the Italian had failed two doping tests for the banned substance clostebol before an independent court ruled that Sinner was neither at fault nor negligent in the positive test.

Sinner successfully argued that the positive tests were the result of contamination, as his physiotherapist had treated a cut on his finger with an over-the-counter spray containing clostebol and then inadvertently transferred it to Sinner through his daily massage treatments. The 23-year-old was successful in overturning the automatic provisional ban, meaning he was able to continue competing for five months without his positive test being publicly disclosed.

It was Paul who set the tone at the start of the fourth round encounter. His all-court game was in full swing from the start as he launched forehands, charged to the net and broke two times to take a 4-1 lead in the first set. After looking sluggish for most of the set, Sinner’s level quickly rose and he fought his way back into the match by crowding inside the baseline and dominating rallies with his far greater pace and weight. In the tiebreak, Sinner smothered Paul with his greater power and narrowly won the first set.

Paul immediately shook off the disappointment of losing the first set and held on to serve brilliantly in the second set. When they met in the second set tiebreak, Paul played his best tennis of the evening to pull within 5-4. The match was dictated by just three serve returns as Paul missed two backhand returns and Sinner then blew a forehand return on set point, allowing him to sink an easy forehand return.

After building a two-set lead, Sinner cruised through the third set to reach the quarterfinals of the US Open for the third time in his career. “The gaps were very small,” Paul said. “That’s a motivation for me. Of course there are two Americans left in the tournament, but somehow it has never felt so open.”

Iga Świątek continued to build momentum in the top half of the field, returning to the quarterfinals with an efficient 6-4, 6-0 win over 16th seed Ludmilla Samsonova. The women’s world number one’s victory paves the way for a thrilling quarterfinal against Jessica Pegula.

Pegula continued her summer renaissance, defeating Diana Shnaider 6-4, 6-2. The fifth-seeded player has now reached seven Grand Slam quarterfinals but is still waiting for her first major semifinal. To break new ground, she will need to topple the best player in the world.