In the bowels of Old Trafford, a cathedral of football for home supporters but a hostile fortress to visiting players, Brenden Aaronson stood in silence facing a mirror in the locker room.If only for a fleeting moment, he’d quiet the outside noise. Quiet his mind. Visualize the 90 minutes ahead of him and his Leeds United teammates. Lock in and, as his trainer would incorporate in his routine pregame text, prepare for battle.“Get ready to go to war,” Aaronson told The Athletic, “that’s all you can do.”Leeds hadn’t won at Old Trafford in 45 years. Manchester United were flying under interim head coach Michael Carrick. Leeds sat precariously just three points above the relegation zone heading into the weekend.No one expected them to pick up three points in Manchester, but outside noise and expectation didn’t matter within the group. What unfolded was a historic 2-1 win. Aaronson picked up an assist, which he admitted with a laugh was “a little bit lucky, but that luck comes around.”Aaronson returned for another quiet moment in the locker room after the final whistle.“Looking back in the mirror after the game, when you see how exhausted I am coming off the pitch, it makes you feel 10 times better about yourself,” Aaronson said.That win is now part of an eight-game unbeaten run in the league, with top-flight survival secured well before the final day of the season. After winning the Championship in 2024-25, Leeds achieved its top goal and even enjoyed a bonus run to the FA Cup semifinals.One of many key cogs is Aaronson, the 25-year-old U.S. men’s national team attacking midfielder who is expected to be named to a second straight World Cup squad next week. He has appeared in more Premier League games (36 of 37) than anyone on the team. He took his game to another level after returning to Leeds from a loan in the summer of 2024, winning back fans along the way and silencing doubters.It’s a natural development and growth from a person who is insatiable in his desire to improve, but it has come with a new weapon in his arsenal: trainer Tareq Azim.Azim, best known for his work with NFL stars like Marshawn Lynch, Justin Tuck, Dion Jordan and others, has been working individually with Aaronson since the fall. It is his first soccer client and one of two athletes he is working with individually this year.That routine of looking in the mirror before and after the game is new for Aaronson. It is merely one manifestation of many from their work together, which quickly morphed to a strong bond. A symbiotic partnership, Azim sought to work with Aaronson.“I wanted to use Brenden as a case study of the power of the individual,” Azim said. “This kid is a f***ing dog.”Brenden Aaronson and Tareq Azim at Elland Road (Courtesy of Tareq Azim)Azim first visited Leeds at the request of his close friend Jed York, the club co-owner who is also the CEO and principal owner of the San Francisco 49ers. York sought Azim’s analysis of the club’s performance model.Azim hadn’t done much work around soccer but has long held a love for the game. A descendant of Afghan nobles, Azim’s family was forced to flee Afghanistan in 1979 and settled in America. He even started playing American football as a kicker because of his connection to soccer, before bulking up and fitting more seamlessly as a linebacker, which is where he played collegiately.In 2004, Azim returned to a war-torn Afghanistan. The destruction had a profound impact on him. It was there, from the rubble of what once was in his homeland, he set up a neighborhood soccer league for kids.As he returned to the Bay Area, Azim began working to diagnose and cure a “disease of fear” with various professional athletes. That list kept growing to the point he opened his own gym, Empower, and authored his memoir by that same name.With that trip to Leeds, Azim was back in soccer. The club listed a number of players for Azim to work with early in the season, but he opted to wait and observe first. He watched a match against West Ham in October and was drawn to Aaronson. Not because he scored in a Leeds win, but his mentality and room for growth.There was a mundane moment where Aaronson hesitated on the ball and lost an opportunity that particularly attracted Azim.“It was the moment I saw him battle with trust,” Azim said. “That hesitation is trust.”After the game, Azim and Aaronson had their first conversation. “I thought, ‘Let me run this moment by him,’” Azim said. “If he agrees with me, then we’re going to rock.”An initial chat meant to be a few minutes quickly turned into an hour and a half. And so Aaronson became the first pro soccer player in what Azim calls his “stable of champions.”“That’s our thing,” Azim said. “Stable of champions and humble animals. It’s real.”