Updated 6:05pm: World number one Novak Djokovic has reached an eighth successive US tennis Open semi-final with victory over Andy Murray.

Djokovic's won 7-6 6-7 6-2 6-4, eventually getting on top after a gruelling first two sets which went over two hours.

He says he and Murray went toe to toe early on.

He says they both gave their best and while it wasn't the prettiest tennis, it was because they were pushing each other.

Djokovic will meet Japan's Kei Nishikori in the semis.