Caroline Wozniacki was put on hold on match point Monday. (Alastair Grant/AP)

Etiquette is a virtue in tennis, not only for the players on court, but also for the fans in the stadium.

Silence is expected before and during points — aside from the occasional “ooh” and the increasingly audible grunts — and a chair umpire won’t hesitate to chastise a fan for being too chatty.

And like in a movie theater, ringing cell phones are a serious no-no. So when a phone ringer went off before match point of Caroline Wozniacki’s first round Swedish Open contest with Alize Cornet on Monday, everyone on court scanned the stands for the guilty party.

Turns out it the phone belonged to Cornet, and the ring was emanating from her bag.

The interruption briefly rattled Wozniacki, who failed to convert on match point and was broken. The world No. 1 regrouped to break Cornet in the ensuing game for a 6-4, 6-4 victory.

But on Wednesday, Wozniacki’s tournament was put on hold once more — this time indefinitely — as she was forced to retire from her second-round match against Sofia Arvidsson due to a shoulder injury.

It’s just the latest setback for a player still looking for her first grand slam title to solidify her top ranking.