The world No. 2 's application was almost rewarded in the sixth but Cilic dug deep to fend off three break points .
Cilic won last year 's final after David Nalbandian was disqualified for kicking an advertising board into a line judge 's shin .
The world No. 2 's application was almost rewarded in the sixth but Cilic , who won last year 's final after David Nalbandian was disqualified for kicking an advertising board into a line judge 's shin , dug deep to fend off three break points .