Andy Roddick has expressed deep concern for Novak Djokovic after the Serb suffered a tough setback in his opening-round match at the 2025 US Open. The former World No. 1 admitted he was left shaken by what he witnessed, adding that it could significantly hinder the former World No. 1's chances of making a strong run at the tournament. Djokovic began his campaign in New York on Sunday, August 24, with a straight-sets win over rising star Learner Tien, 6-1, 7-6(3), 6-2. Despite the comfortable scoreline, the Serb appeared far from his best as he struggled with a painful blister, which visibly affected him throughout the match. The Serb breezed through the first set, but things turned complicated in the second as he appeared physically hampered and had to stretch it to a tiebreak. He even called for a medical timeout, with the physio attending to a troubling foot issue. Cameras zoomed in to reveal a large blister on his foot. Later, on his 'Served with Andy Roddick' podcast, the American admitted he found the blister “gross” to look at. Roddick also confessed he was genuinely worried for Novak Djokovic during the match, saying he doubted whether the Serb would even make it past the second set given how much pain he seemed to be in."The blister looked gross," Roddick said (at 3:40). "We didn't even there was a blister. You can't fake match conditions in real life tournament. At one point I was like, 'If Novak wins the second set, that might be it.' There was a legit concern. I didn't know there was a blister and then he took his shoe off. That thing was disgusting. That was a gross blister. Half of the skin of his foot was hanging off.""But Novak is able to manage pain conditions by shortening the points early. Two days is a long time to get stuff right but maybe not when your foot is hanging off from the edge of earth. Props to Novak for getting through. That thing was nasty and I also think there were some physical issues there. Maybe it's from not playing for a while," he added.Novak Djokovic after US Open 1R win: "I really was surprised how bad I was feeling"Novak Djokovic pictured at the 2025 US Open | Image Source: GettyNovak Djokovic addressed the blister that troubled him in his first-round clash against Learner Tien at the 2025 US Open during his post-match press conference. He admitted he was “surprised” by how his body reacted but reassured that it was nothing serious, stressing there were no injury concerns going forward.Djokovic said:"I really was surprised how bad I was feeling in the second physically. It's slightly a concern. I don't know. I don't have any injury or anything. I just struggled a lot to stay in long exchanges and recover after points."The 24-time Grand Slam champion will next face the USA's Zachary Svajda on Wednesday, August 27. It will mark their first-ever meeting on the ATP Tour.