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HARRISON, N.J. — It was probably fitting that John Rooney’s game-winning goal in the Red Bulls’ Lamar Hunt U.S. Open Cup victory Tuesday night was not a scorching blast into the upper corner, but rather a well-placed shot into the bottom corner that had barely enough speed to beat F.C. New York’s keeper.

Rooney’s shot in the 65th minute completed the Red Bulls’ comeback in the third-round tournament match and drew chants of “Best Rooney Ever” from the crowd at Red Bull Arena. That is subjective, of course, because he is the younger brother of Manchester United’s superstar Wayne Rooney and had previously played only 27 minutes this season in all competitions.

Coach Hans Backe said John Rooney stuck out at the 2011 M.L.S. player combine in January as one of the best central midfielders, but there is still one thing holding him back from being a significant contributor to the team.

“It’s definitely about his pace,” Backe said. “His understanding of the game is very good, he’s a good passer of the ball, he has a good strike, but it’s all about his pace. He just has to be a little bit quicker and sharper in possession.”

Returning United States national team members Juan Agudelo and Tim Ream joined a team of mostly reserve players in the match against F.C. New York of the United Soccer Leagues. Mainly, the game was an opportunity for seldom-used players like Rooney to play while the starters rest before for Saturday’s trip to San Jose, Calif., and after a long three-game road trip.

While he is still more well-known for his surname than his on-field accomplishments, Rooney has been putting in extra work to improve his quickness ever since he was selected by the Red Bulls in the draft. At 5 feet 10, and 176 pounds, he has his brother’s build, but not quite the speed necessary to crack the Red Bulls’ starting 11. The Red Bull coaching staff made it clear before the season exactly what they wanted him to focus on.

“Since I arrived here, that’s one of the main things I’ve liked to work on,” he said. “I’m comfortable with the ball, but I like to work on my pace. It’s a thing I’ve worked on most days after training with the fitness coach.”

After playing on Everton’s youth squad in England with his two brothers, John Rooney, a native of Liverpool, joined Macclesfield Town of English League 2, which is essentially England’s third fourth-tier league, in 2008 and stayed there until making the jump to M.L.S. this year.

“It’s a physical league,” he said. “I thought it was going to be slower than what it was, but when I watched it on TV, you could see it’s a fast league. The way they play it, it’s pretty much the same as England.”

Thanks to his second-half goal, which came seven minutes after his fellow M.L.S. rookie Corey Hertzog scored the first goal to tie the game, Rooney and the other reserves will get another shot at first-team time time on July 12, when they travel to Chicago to play the Fire in the quarterfinals of the Open Cup. Backe said he would use a similar lineup against Chicago, which beat the Rochester Rhinos, 1-0, Tuesday in another third-round game, because of the Red Bulls’ busy July schedule.

In addition to six league matches and the Chicago game, the team goes to London to play in Arsenal’s Emirates Cup on July 30 and 31.

“If we hadn’t had this kind of schedule, then definitely we could have prioritized to win the Cup,” Backe said. “But with the schedule it is now, we can’t do it.”

The Open Cup winner will earn a berth in the 2012-13 Concacaf Champions League.