Indian Wells champions <a href="https://www.thenationalnews.com/tags/carlos-alcaraz/" target="_blank">Carlos Alcaraz</a> and Elena Rybakina on Tuesday stayed on course to complete the 'sunshine double' at the Miami Open but men's second seed Stefanos Tsitsipas was sent packing by Karen Khachanov. World No 1 Alcaraz beat Tommy Paul 6-4, 6-4 in the fourth round, while Rybakina notched up her 12th straight win with a 6-3, 6-0 thrashing of Martina Trevisan to reach the semi-finals. Paul had beaten Alcaraz in their only previous meeting at last year's Rogers Cup but was no match for the Spaniard on this occasion, the top seed showcasing his sensational speed and reflexes to take early breaks in both sets. Defending champion Alcaraz was denied on his first match point but was soon letting out a mighty roar when Paul sent a forehand long to end the match. "The key of that match was that I was playing to attack," Alcaraz said. "I didn't let him play his game - attack and go to the net - I did those things first. I played a really complete match." Alcaraz is now three wins away from securing the 'sunshine double' after his victory at Indian Wells last week - a triumph that would see him retain the world No 1 ranking ahead of Novak Djokovic. In the quarter-finals, the Spaniard will play another American in Taylor Fritz, who eased past Denmark's Holger Rune 6-3, 6-4 earlier in the day. Daniil Medvedev swept aside Quentyn Halys 6-4, 6-2 in just over an hour in a contest that started after midnight, sealing his place in the quarter-finals for the third successive year when the Frenchman netted a backhand. "I thought it was going to be cancelled," Medvedev said. "Really happy that I was able to play not so bad. I'm usually asleep at midnight." At the Grandstand, Italian 10th seed Jannik Sinner breezed past sixth seed Andrey Rublev, firing off more than two dozen winners to win 6-2, 6-4. Khachanov, seeded 14th, earned his first win over Tsitsipas in seven meetings, taking down the Greek world No 3 7-6, 6-4 in the fourth round to end a 23-match winless run against top-10 opponents. Tsitsipas never found his best level against Khachanov, who controlled the match with a rock-solid serve. "They say third time is a charm, but for me it took seven times, so I'm super happy," said Khachanov, who lost to Tsitsipas in the semi-finals of this year's Australian Open. "Not most importantly that I beat Stefanos, but I think with the way I'm playing, I'm just happy to continue that level." Wimbledon champion Rybakina has been in rare form this year after reaching the final of the Australian Open and was hardly troubled as she extended her winning streak. The 10th seed deployed her clean groundstrokes and feasted on Italian 25th seed Trevisan's soft second serve in the tight first set. But it was all Rybakina in the second, the powerful and precise Kazakh pounding an unreturnable serve on match point to set up a last-four meeting with Jessica Pegula, who rallied to beat Anastasia Potapova 4-6 6-3 7-6(2) in a late-night thriller. "Maybe I'm moving not as good as I was moving in Indian Wells but overall I think that I'm trying to keep that level from Indian Wells," said Rybakina. "There are a lot of ups-and-downs, but I think overall it's not bad." World No 3 Pegula saved two match points late in the third set before dominating in the tiebreaker. The match was hit with a near four-hour rain delay before Pegula sealed her spot in the semi-finals for the second straight year.