Claressa Shields said she would have more power behind her shots on Saturday night and proved true to her word as she stepped up in weight, dropping and stopping Vanessa Lepage-Joanisse in the second round and adding the WBC heavyweight and WBO light heavyweight titles to her overflowing collection at the Little Caesars Arena in Detroit. The fight was fought at 175 pounds, which the WBC refers to as heavyweight for women.

Shields (15-0, 3 KOs), an Olympic gold medalist in 2012 and 2016, needed little time to impose herself against the defending champion from Quebec, Canada. A left hook buzzed Lepage-Joanisse (7-2, 2 KOs) in the first, prompting Shields to unleash a furious flurry to finish the round.

Lepage-Joanisse attempted to push Shields backward in the second, but a counter right hand off the ropes dropped her hard onto her back. After Lepage-Joanisse rose to her feet, Shields immediately went on the attack, dropping her opponent again with another right hand. Lepage-Joanisse's corner stood on the ring apron, apparently ready to throw in the towel, but Shields kept going, dropping her foe a third time and prompting the stoppage.

“I shocked myself, I'm not gonna lie,” Shields said afterward. “I went in there real slow in the first round because I'm no dummy.” But, she told interviewer Al Bernstein, once she felt she hurt her opponent with that first-round left hook, she went for the finish.

“I knew I was strong in camp, but I was super-strong tonight,” she said. “Maybe I'll stay at heavyweight.”

Kieran Mulvaney has written, broadcast and podcasted about boxing for HBO, Showtime, ESPN and Reuters, among other outlets. He also writes regularly for National Geographic, has written several books on the Arctic and Antarctic, and is at his happiest hanging out with wild polar bears. His website is www.kieranmulvaney.com.