American Jack Sock ended Kei Nishikori's streak of a third straight WTA Tour title, while Grigor Dimitro is also out of the race at the Shanghai Rolex Masters in China on Wednesday.

Sock, 22, defeated the seventh seeded Japanese in two straight sets 7(7)-6(5) 6-4 in a match that lasted an hour and 24 minutes.

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The win on Nishikori is the American's first win over a top 10 seeded player.

Sock is also participating in the doubles event along with partner Canadian Vasek Pospisil who lost his singles matchup against 14^th seeded Roberto Bautista Agut in a heart-breaking three setter.

Nishikori came to Shanghai with two back-to-back titles in Kuala Lumpur and Tokyo. He is currently No. 5 in the eight-man short list for the year-ending ATP World Tour Finals to be held in London and aims to become the first ever Asian player to qualify for the event.

Another hopeful for the season-ending event is Bulgarian star Grigor Dimitrov who fell short of his quest after being defeated by the recent Malaysian Open runner-up Julien Benneteau of France also in two sets 7-5 6-3.

The 10^th seeded Dimitrov is currentl 11^th in the list of London hopefuls and with his early exit, his chances of making it to the prestigious event grows dimmer.

Benneteau and Sock are set to battle it out in the third round.

Another London hopeful is Britain's No. 1 Andy Murray who won against Poland's Jerzy Janowicz in straight sets 7-5 6-2.

The 11^th seeded Murray will face David Ferrer who came back from behind to win his match against Slovakian Martin Klizan earlier.

Murray and Ferrer are currently 9^th and 10^th place in the road to London and still have a fighting chance of surpassing Milos Raonic and Tomas Berdych if they reach the finals of the tournament.

World No. 1 Novak Djokovic and sixth seeded Berdych are currently a set ahead of their opponent as of press time.

TagsKei Nishikori, Jack Sock, Grigor Dimitrov, andy murray, David Ferrer