1. double fault - Noun
2. double fault - Verb
(tennis) two successive faults in serving resulting in the loss of the point
Source: WordNetdouble-fault
The match seemed destined to go to a tiebreaker, but when Raonic gave up a double fault, he conceded the break point and Nishikori put it away. Source: Internet
The Belgian pulled a break back in the second set but then trailed 5-0 as the top seed punched a ticket for the last eight when Mertens served a double fault on the first match point. Source: Internet