World No 1 remains undaunted by losses at tune-up events

World No 1 Novak Djokovic could not reach the final of his two US Open tune-ups, but he likes his chances to reach a fourth consecutive US Open final.

The 26-year-old Serbian star, who won his fourth Australian Open title and sixth Grand Slam crown earlier this year, fell to eventual winner Rafael Nadal in a French Open semifinal and to Britain's Andy Murray in last month's Wimbledon final.