Defending champion Carlos Alcaraz through to fourth round in Miami

Defending champion Carlos Alcaraz moved into the fourth round of the Miami Open after seeing off Dusan Lajovic in straight sets.

The 19-year-old Spaniard, who returned to the world number one spot last week as he lifted the trophy in Indian Wells, emerged with a 6-0 7-6 victory from a contest lasting just over 90 minutes.

The first set took just 32 minutes as Alcaraz broke his Serbian opponent in the opening game and did not let up en route to a whitewash.

In the second he suffered his first break of serve at 5-4 before going on to secure victory via the tie break.

Alcaraz said in quotes on atptour.com: “I feel fast on court, I am moving well.

“I am happy with the variety I am playing (with). Lots of shots. I am enjoying every single second out there.”

Alcaraz, who will prevent Novak Djokovic from replacing him at the top the world rankings if he retains the Miami title, will next face Tommy Paul, a 6-3 7-5 victor over Alejandro Davidovich Fokina.

Third seed Casper Ruud was defeated in an upset at the hands of 27-year-old Botic van de Zandschulp in three sets.

The Dutchman won in just under three hours of play, saving 13 from 15 break points en route to a 3-6 6-3 6-4 win.

The victory for the 26th seed was his first against a top five player and he will go on to play the Finnish 23-year-old Emil Ruusuvuori in the fourth round.

Meanwhile, sixth seed Andrey Rublev made tidy work of Serbian Miomir Kecmanovic, winning 6-1 6-2 in just 58 minutes.

Brought his A-game