Carlos Alcaraz dismissed Jiri Lehecka in a sparkling 6-4, 6-2, 6-4 masterclass to reach the semi-finals at the US Open on Tuesday. 

The Spanish second seed, who is seeking his second title in New York and sixth Grand Slam crown, has yet to drop a set at this year's tournament. The scoreline does not, however, reflect the quality of the match, which featured a dazzling array of shots from both men. 

A magnificent display of serving from Alcaraz ultimately made the difference, with the Spaniard surrendering just seven of 45 points behind his first serve and facing no break points during their one-hour, 56-minute clash. Alcaraz will meet Novak Djokovic in the last four. 

"It's really difficult not to think about it. Every time I step on the court, I try not to think about it. I think if I think about the number one spot too much, then I'm going to put pressure on myself, and I don't want to do that. I just want to step on the court, try to do my thing, follow my goals, and try to enjoy as much as I can. The number one is there, but I try not to think so much about it," said Alcaraz. 

On the women's side, No. 4 seed and last year's runner-up Jessica Pegula reached the second major semi-final of her career with a 6-3, 6-3 defeat of Barbora Krejcikova on Tuesday. 

After saving eight match points against Taylor Townsend in her previous match that lasted more than three hours, a weary-looking Krejcikova struggled against Pegula, who in contrast had conceded just 17 games en route to the quarters. 

Pegula broke in the second game of the opening set before Krejcikova rallied to get back on serve at 3-4. But the American held firm and Krejcikova dipped again to lose the next two games and the set. 

Krejcikova quickly fell behind 4-1 in the second set, but once again she reduced the deficit to 3-4 before Pegula powered through to close out the match. The unseeded Czech finished with 24 unforced errors, including seven double faults, to only 14 winners, while Pegula tallied 17 winners to 20 unforced errors. Pegula will face top seed Aryna Sabalenka in the last four.