Daniil Medvedev reached a fifth straight ATP Tour final with a hard-fought victory over his Russian compatriot Karen Khachanov in the Miami Open.

Medvedev needed two hours and 17 minutes to battle past his good friend Khachanov, winning 7-6 (5), 3-6, 6-3 to set up a showdown with 10th seed Jannik Sinner. The last player to reach five consecutive finals on the ATP Tour was Ivan Lendl in 1981.

Medvedev hit 13 aces and saved four of six break points as the match turned decisively in his favor when he broke Khachanov in the fourth game of the third set.

Medvedev won 82 percent (14 of 17) of his first-serve points in the final set and was relieved to have beaten a player who knows his game so well.

"In my opinion, it was a top match," Medvedev said. "In the first set when we lost our serves, it was just a good game from the returner.

"In the second set, I had one bad game and he won the set. I had one break point, I could have done better. He had a break point in the first game of the third set, I managed to play well. He had one bad game in the third set, I managed to take it and I am really happy to be through. It was a very tough match."

In the other semifinal, Sinner ended Carlos Alcaraz's reign as world number one, triumphing 6-7 (4/7), 6-4, 6-2.  

The disappointment for the 19-year-old Alcaraz, the defending champion in Miami and coming off a title at Indian Wells, will be tinged with frustration after he struggled in the third set with leg cramps. 

It had been an enthralling and entertaining power-hitting performance from both men in the first set, won by the Spaniard after a tie-break, but an inspired Sinner fought back in the second. 

Sinner broke in the first game and although Alcaraz broke back to make it 2-2, the 21-year-old Italian sensed his moment was arriving and showed confidence in his powerful groundstrokes. 

Sinner broke again to go 5-4 up and then held for the set to end Alcaraz's streak of 21 winning sets.

The world number one was moving with difficulty and was broken on his first serve in the deciding set. Looking in discomfort, he crouched down on his baseline in between points and shot some worried and confused looks to his team in the stands.

Sinner lost his focus for a while, his blistering shots replaced by some conservative strokes but he soon regained focus as he ran out the winner in three hours.