Australia's wild card Thanasi Kokkinakis caused a huge upset by defeating World number one and defending champion Roger Federer at the Miami Open on Saturday.

With his second consecutive defeat, Roger Federer is set to loose his no.1 spot in the rankings, he gained in February after winning the title in Rotterdam. Swiss master required to reach QF to be on the top spot.

Big serving qualifier ranked 175th in the world Thanasi Kokkinakis ousted the current world no.1 Federer in three thrilling sets 3-6, 6-3, 7-6 (4).

Kokkinakis became the lowest-ranked man to beat a No. 1 player since No. 178 Francisco Clavet upset Lleyton Hewitt in 2003. Federer will lose his current spot to Rafael Nadal when the rankings will be updated on April 2nd.

Swiss maestro looked firmly in control after first set where he didn't even faced a break point and drop just six points in his own serve to win it by 6-3.

But Kokkinakis came back strongly in the second set by breaking Federer's serve to take 3-1 lead and push the things into the decider set.

Federer looked impassable again on his serve in third set but failed to capitalize on two break points he had in a marathon sixth game, as they went on serve to the tiebreaker.

Two initial errors from world no.1, gave Aussie a 4-3 lead and a strong forehand winner put him in a commanding position by 6-4 as he won the match by 3-6, 6-3, 7-6 (4).

“It’s pretty crazy. I’m pretty happy about it,” Kokkinakis said after his historic win over 17-time Grand Slam champion Roger Federer.

Also Read: 20 Golden moments from Roger Federer’s career

Despite the defeat, Federer reassured that he will not play in the clay season again for more ranking points.

Nadal will become the new No. 1 even though he missed Key Biscayne because of a hip injury that also forced him to skip Indian Wells.