On charity event at Dubai, Murray beat Djokovic by winning six games and losing three games.
Note: There is total of 5 service breaks(one who serve lost the game).
Who served first, Djokovic or Murray?

Murray serves first

The one who serves first can serve 5 and other will serve four.
Case-1 :
If Murray serve 4 and Djokovic serve 5
Then five service breaks and Murray winning 6:3 not possible.

Case-2 :
Murray serve 5 and Djokovic serve 4
There are five service breaks and score is Murray 6 - Djokovic 3
On Murray serve, Murray wins 3 and lost 2
On Djokovic serve, Murray wins 3 and lost 1