WASHINGTON -- New York Red Bulls fullback Jeremy Hall almost had to do a double take. Sure he knew his buddy was with rival D.C. United, but seeing Rodney Wallace and playing against him are two entirely different things.In college, their roles were reversed. Hall was the left-sided midfielder, while Wallace was the left back who made the overlapping runs. They were both big parts of Maryland's NCAA championship run.Their first head-to-head meeting in Major League Soccer was April 26, with Wallace scoring his first professional goal in D.C. United's remarkable come-from-behind 3-2 victory at Giants Stadium."To match up against him, it was a little weird a few times," Hall said. "He got to take me on a couple of times and it was weird me playing defense and him running at me. It was fun though."The second meeting was in a Lamar Hunt U.S. Open Cup play-in game Wednesday night. This time, Wallace came off the bench and while he didn't score, D.C. again prevailed, beating the Red Bulls 5-3 at RFK Stadium."It was definitely weird because Jeremy and I are really close and we're used to playing on the same side and connecting with each other," Wallace said. "The first game we played against each other was really strange. It's like going up against your best friend."A native of Rockville, Md., Wallace was able to stay in the area, selected by D.C. United sixth overall in the 2009 MLS SuperDraft. Hall went to the rival Red Bulls with the 11th overall pick. Both have made immediate impacts on their teams."He's doing really well. Rodney's a good player and he plays hard every time he's on the field," Hall said. "He did that in college and he's doing that now. I think he's doing a great job with D.C."Hall was first thought to be the left midfielder to fill the void after Dave van den Bergh was traded to FC Dallas, but instead Red Bulls coach Juan Carlos Osorio moved him to right back, a position he played with the U.S. under-17 national team.Hall has started four of the six games he's appeared in, but that number is expected to increase substantially after Costa Rican international Carlos Johnson broke the fifth metatarsal in his left foot last Saturday against Houston. Johnson had successful surgery on Tuesday night and is expected to be sidelined for at least 6-8 weeks."When we look back, I think it is good Jeremy already has played well," Osorio said. "You guys remember I brought him in the first game against Seattle in the 30th minute. From then on he has played well and he has contributed. We think he has matured and hopefully he keeps showing some consistency in his playing. We are more than comfortable with him in that position."Wallace, meanwhile, has found his niche wide on the right of D.C.'s five-man midfield. He has started all 10 of United's games and already has two goals and three assists on the season."He's really open-minded and he listens to everybody," D.C. defender Marc Burch said. "He's a great student of the game. He knows how to use his abilities and he does it well. He works hard for 90 minutes, he has a great touch, he can get around people. I couldn't imagine a better formation for him than a 3-5-2."Like Hall, Wallace has been able to ease the transition from college to pro because of his sheer athleticism."Rodney Wallace, a.k.a. the Greyhound, which is what I like to call him, is so full of athleticism that I think it helped him to buffer that gap and transition period," D.C. defender Bryan Namoff said. "It was a position we really needed to fill and because he is so athletic, he jumped in there and started having success early on."Wallace said playing under Sasho Cirovski at Maryland is a big reason why he and Hall have been able to contribute right away."We both came out of a good program and we were already sort of in a professional environment," Wallace said. "Jeremy is a great player and I'm not surprised that it didn't take him much to get on the field."