Novak Djokovic: World number one sees off Berdych in Miami

Djokovic has won 11 Grand Slam singles titles

World number one Novak Djokovic extended his winning run over Tomas Berdych to 10 matches with a straight-sets win at the Miami Open.

The top seed won their quarter-final 6-3 6-3 and will next face Belgian David Goffin.

Djokovic had treatment on his back in the second set, but asked about the issue he told BBC Sport: "No concerns, not at all."

The 28-year-old is trying to win his sixth Miami title and third in a row.

It is three years since Berdych earned one of only two wins over Djokovic in 24 meetings - and again it was the Serb who dominated.

Djokovic gets treatment on his back

In blustery conditions, Djokovic broke twice in the first set and he took control of the second after Berdych followed a woeful smash with a double fault.

The only alarm came when he called the trainer, but Djokovic resumed in the same dominant form and sealed victory with another service break.

"I was trying to find the rhythm on the serve," he said. "Evidently we both struggled with that.

"The swirly conditions on the court were quite tough. Once you toss the ball you can't predict where it's going to end up.

"That's why I had a little bit of a spasm in the back but Paul from the ATP did a great job."

Djokovic and Victoria Azarenka remain on course for the Indian Wells-Miami double, after both won in California two weeks ago.

Kerber won the Australian Open in January

Two-time Miami champion Azarenka, who reached the semi-finals with a 6-4 6-2 win over Britain's Johanna Konta, will play German second seed Angelique Kerber on Thursday.

"I still feel that I'm far from my best and that's what's really exciting for me, to be motivated, to keep improving," said Azarenka.

Kerber impressed in a 6-3 6-2 defeat of American Madison Keys, setting up a rematch with Azarenka after she beat the Belarusian on her way to winning the Australian Open in January.

"She had a great start of the year, of course," said Kerber. "She is on fire, I think, right now."