Breanna Stewart helped the New York Liberty earn a 76-69 win against the Phoenix Mercury on Sunday in Game 1 of their first-round playoff matchup. However, Stewart was hobbling late in overtime after seemingly injuring her right knee.Midway through overtime, Stewart drove to the basket and finished a tough layup plus the foul. She grabbed her left knee after the play and was in pain as the Liberty called for a timeout. She shot the bonus free throw and missed but was hobbling in the next few possessions.Stewart was subbed out at the 2:07 mark, with Leonie Fiebich hitting the dagger 3-point shot with under a minute left. The three-time WNBA champ finished with 18 points, six rebounds, four assists and two steals on 7-for-14 shooting.Here's the video of the apparent left knee injury.New York Liberty coach Sandy Brondello didn't have an update about Breanna Stewart's left knee injury after the game. Brondello told reporters that Stewart was in pain and asked to be evaluated. The defending champions are back in Brooklyn on Wednesday for Game 2.Despite the injury, Stewart left the game and entered the locker room walking under her own power. However, she was gingerly walking and had a brace on her left knee, based on the video uploaded by Desert Wave Media on X.Natasha Cloud had a team-high 23 points on 9-for-12 shooting, plus six rebounds, five assists and four steals. Sabrina Ionescu struggled with her shot, but she still finished with 16 points, six rebounds and seven assists.Breanna Stewart had a right knee injury this seasonBreanna Stewart had a right knee injury this season. (Photo: IMAGN)It has been a tough season for Breanna Stewart in terms of injury. Stewart missed 13 games due to a right knee injury suffered on July 26 against the LA Sparks. She was diagnosed with a bone bruise in her right knee, returning on Aug. 25 in a win over the Connecticut Sun.Stewart has been durable for the majority of her career, outside of a torn left Achilles that kept her out for the entire 2019 season. She's vital to the Liberty's success, so it will be interesting to see if she'll be cleared by Wednesday.The defending champions have a chance at sweeping the Phoenix Mercury in the first round and advancing to the playoff semifinals against either the Minnesota Lynx or Golden State Valkyries.