In pictures: the world's highest tennis court

1 of 7 Tennis stars Andre Agassi and Roger Federer turned into stunt men to play on the world's most unique tennis court to launch the Dubai Duty Free Men's Open tennis tournament

2 of 7 The helipad of a luxury hotel in Dubai was transformed into a tennis court for the stunt

3 of 7 The hotel stands at 321 metres on a man-made island, with the helipad jutting out over the sea 211 metres below

4 of 7 It's therefore probably not a good idea to look down, Andre

5 of 7 Luckily ball boys and girls were not required to run up and down the hundreds of steps to retrieve balls from the sea below

6 of 7 Roger Federer throws the ball in the air for a 211metre-high serve

7 of 7 And even runs for a shot! Fortunately the brave players managed to stop themselves from going over the edge