Konta and V Williams in Miami semis

World number one Angie Kerber has once again been frustrated, beaten at the quarter final stage of the Miami Open.

With 12 wins and 7 losses, and one semi final appearance in Dubai her best result in 2017, the top spot taken from Serena Williams is fast becoming a statistical rather than factual representation.

Interesting that it was Serena's sister who stopped the Miami run of Kerber with an impressive straight sets victory.

Venus now has a semi final appointment with 10th seed Johanna Konta, whose revival against 3rd seed Simona Halep deserves praise.

Halep took the opening set 6-3, winning an incredible percentage of points on her second serve, and had the chance to serve for the match at 5-4 in the second set.

Konta was only two points from defeat before managing her revival, taking the set to a tie break which she eventually won 9 points to 7.

The deciding set was an exhibition from Konta, as Halep lost all focus and the match.

3-6 7-6 6-2 and the Australian born English player will be hard to stop from here.

Of course, others have just as valid claims, and they feature in the first of the semi finals.  Second seed Karolina Pliskova and 12th seed Caroline Wozniacki have performed well throughout the tournament, and their respective quarter finals were no exception.

Pliskova exacted some revenge for her unexpected quarter final loss to Mirjana Lucic-Baroni in the Aus Open in January by eliminating the Croatian here 6-3 6-4.  Ten double faults from Mirjana didn't help.

Wozniacki beat Lucie Safarova in her quarter final 6-4 6-3, and was especially solid on her serve in the second set.  She will need that in her battle with Pliskova.

One of the men's semis is confirmed and it is a surprise.  Rafa Nadal would not have picked Fabio Fognini as his opponent in the final four.

Fognini knocked out second seed and last year's runner-up Kei Nishikori in just over an hour.  This is unseeded Fognini's second appearance in a Masters 1000 semi final.

Nadal reached the final four by dismissing 13th seed Jack Sock 6-2 6-3.

The other semi final will be decided with two quarter finals, one from the old stagers Roger Federer and Tomas Berdych, the other from NewGen - Alexander Zverev and Nick Kyrgios.

Federer last played, and beat, Berdych en route to the Aus Open crown in January, while Kyrgios played Zverev for the first time just a week or so back in Indian Wells with the Aussie prevailing.