Tennis: Djokovic Sets New Record As He Defeats Kei Nishikori At ATP Finals

Novak Djokovic was yet again a class apart as he claimed a record 15th straight ATP World Tour Finals victory in the first game of the tournament against Kei Nishikori.

The world number one has won the season-ending extravaganza three years in a row and it is difficult to envisage him failing to triumph for a fifth time in total in London.

Djokovic stretched his winning run to 23 matches by outclassing Nishikori, coasting to a 6-1 6-1 victory in the Group Stan Smith opener at the O2 Arena in only 65 minutes - and breaking the record for the longest winning run in the tournament.

US OPEN: Serena, Nadal Progresses To Round Two

Serena Williams and Rafael Nadal lived up to their billing with victories in the first of this year's US Open night sessions.

Top seed Williams needed just 30 minutes to begin her bid for a first calendar Grand Slam as Vitalia Diatchenko retired at 6-2 2-0 down.

Nadal, seeded eighth, saw off 18-year-old Borna Coric 6-3 6-2 4-6 6-4. World number one Novak Djokovic went through, but fourth seed Kei Nishikori was beaten.

TENNIS: Kei Nishikori Becomes First Japanese To Win Barcelona Open

Nishikori dropped his opening service game against Giraldo, who was facing the biggest match of his career, but quickly found his rhythm and broke back with the Colombian losing his serve on a double fault.

Giraldo was hitting the ball well but Nishikori showed his superiority from the base line as he invariably won the longer rallies and broke twice more to take first set comfortably.