Aaronson completed a $30 million move to the Premier League side from FC Salzburg shortly after that final day on May 22, but survival was contingent on Leeds getting a better result than Burnley and avoiding relegation.
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Aaronson said he was in Vienna watching the game with his girlfriend and rode the same emotional rollercoaster that the club's fans did, pacing around the cafe to work off his nerves. He added that his girlfriend was constantly refreshing the Burnley score on her phone.
"Watching there and sitting there, it was just probably one of the most awful watches in my life," Aaronson said during a roundtable with reporters. "I was telling my girlfriend, '[You] watch, I have to go to the bathroom,' like four or five times. It was tough for me, but I mean they got the job done. I'm happy for that.
"I wanted to be part of the club so bad. That game meant a lot to me."
The move sees Aaronson reunited with Leeds manager Jesse Marsch, who worked with the player when the two were at Salzburg. But Aaronson had drawn Leeds' interest prior to Marsch's hiring, and said his affinity for the club runs deeper than being managed by his old mentor.
"Yeah, it's a factor, that Jesse was there, but it was all about me wanting to be at the club in general," he said. "It's a historic club. It's a big club, and I want to be a part of history for them."
The former Philadelphia Union player is expected to feature for the U.S. in those matches, and it's one of the last times he'll be able to impress manager Gregg Berhalter prior to the World Cup in November. Aaronson acknowledged he's taking a risk by moving to the Premier League just ahead of Qatar.
"I think you have to play well for your country, but I think it's also playing consistently week in, week out for your club," he said. "But for me, it's it was a step I wanted to take. I thought it was the right time to up my game by going to the Premier League. And yeah, it's definitely a risk, but it was a risk I was willing to take."
Aaronson also feels he fits the bill of what is expected of a Leeds player, one that isn't all that different from players for teams in his hometown of Philadelphia.
"I got a little, I guess definition about the player that Leeds want, and I think I fit that," he said. "They celebrate a tackle like a goal, and I'm going to be that guy that's not only going to be the creative outlet or the guy that's going to be playing I guess, the [No.] 10 or winger or whatever.
"I'm going to be the guy that's going to be working hard too and that's what Leeds is."
Now Aaronson is ready to put his energies on the field, rather than watch from afar.
"You can tell how passionate the fans are," he said. "I mean, from watching them for about half a year now, you can hear the fans echo in the stadium. You know how football is a way of culture there. It's huge for them. I talked to Jesse a little bit about it.
"The fans, they're amazing, you know, and they're always going to support you. It's tough, and maybe [with] the media and stuff like that, but that's something I'm ready for. And I want to challenge myself mentally and physically."