MIAMI (AFP) — Defending Miami Open champion Daniil Medvedev and top seed Carlos Alcaraz marched into the quarterfinals of the tournament on Tuesday with convincing victories.

Medvedev earned a 7-6 (7/5), 6-0 win over Germany's Dominik Koepfer while Alcaraz took care of Italian Lorenzo Musetti with a 6-3, 6-3 win in 85 minutes.

Second seed Jannik Sinner of Italy also moved into the Last Eight after beating Christopher O'Connell of Australia 6-4, 6-3.

Alcaraz, who is searching for the "Sunshine Double" after winning in Indian Wells, was too much for 23rd seed Musetti although the Italian certainly contributed to a crowd-pleasing contest.

Stadium court erupted after a rally in the third game of the second set saw Musetti clip the ball between his legs, lobbing Alcaraz but the Spaniard returned it with a "tweener" only to lose the point to a deft volley at the net.

But overall it was a comfortable match for Alcaraz whose all-round game looks in strong shape.

"I don't know if this is the best game I've played but without a doubt it is the best feeling. I feel great on the court, I'm moving great, I am not injured and not thinking about my ankle anymore. It's the best feeling since the summer," he added.

In the quarters, Alcaraz will face Bulgarian Grigor Dimitrov, who beat Pole Hubert Hurkacz, triumphing in a third set tie-break for a 3-6, 6-3, 7-6 (7/3) win.

Medvedev made an unusually sloppy start on Stadium court, with a series of unforced errors, and found himself trailing 4-0 in the first set tie-break.

But having overturned that deficit, Medvedev went on to win all the remaining games as he showed that, despite his concerns over the rapid deterioration of balls on the hardcourt surface, he is comfortable with the conditions.

The Russian suggested that Koepfer had struggled to recover from the blow of seeing his tie-break lead vanish.