One destroyed racket — and one poor set — later, Serena Williams is safely into the third round of the Rio Olympics as she bids for a second consecutive singles gold medal.

The No. 1-seeded American struggled for quite a while Monday night before emerging with a 7-6 (5), 6-2 victory over France’s Alize Cornet.

advertisement | advertise on newsday

Williams started off by taking the first three games, but then dropped five of the following six. During that troublesome stretch, Williams reacted to losing two games in a row by mangling her equipment, slamming it against the back of her sideline chair.

Later, she was forced to erase a pair of set points for Cornet, who had won four of their previous seven matchups.

But Williams claimed the last three points of the tiebreaker, raced to a 3-0 lead in the second set and was on her way.

No tennis player ever has won two Olympic singles golds — let alone two in a row.