Ireland continued the trend of heavily favoured teams starting slowly in their opening matches at the tournament before ultimately winning, following in the foot steps of France, England, Scotland and Australia.
A series of handling errors and the tournament's latest wayward kicking performance prevented the Irish from capitalizing on their forward domination until Bowe crossed at the end of the first half.
Jonathan Sexton converted to make it 10-0 but missed another four efforts before Ronan O'Gara took over kicking duties. Hooker Rory Best crashed over 15 minutes into the second half and Bowe rounded off a free-flowing handling move to put Ireland clear.
The U.S. Eagles played their part and provided some highlights of their own, none more so than the final act of the match.
Centre Paul Emerick intercepted the ball and ran almost 50 metres to score under the posts and cut the final margin to 12 points. The near capacity crowd of 24,000, which had roared its way through the match, erupted for one final time
The Eagles had attended an emotional memorial service before the match to commemorate the 10th anniversary of the Sept. 11 terror attacks, and captain Todd Clever later put his team's loss into perspective.
"In the grand scheme of things, this is just a game and we're talking about thousands of lives (lost)," he said. "I'm glad we were able to pay our respects to them and we had a lot of guys cheering for us here and from across the world.
"I'm extremely proud of the boys. We put it all on the table today, we were under a lot of pressure."
Ireland captain Brian O'Driscoll wasn't happy with the performance as his team attempts to progress beyond the quarterfinals for the first time at the World Cup.
"We didn't play well and we really had to fight for our win. I suppose it's job done but we've got a hell of a lot to improve on," O'Driscoll said. "Our set-piece was very good, but we just turned the ball over way too much and we couldn't get any continuity and I think our performance was typified by the last play of the game — we were just a little bit loose."
The team's lineout was efficient and the scrum laid the foundation, continually driving the Eagles forwards backwards with lock Paul O'Connell a dominant presence.
Ireland coach Declan Kidney's gamble of starting inexperienced scrumhalf Conor Murray didn't pay off. He was often too hesitant and, despite making some good runs, the lift in tempo when he was replaced by Eoin Reddan was noticeable.
For the Americans, Clever was inspirational while scrumhalf Mike Petri excelled behind a beaten pack.
The first half was plagued by handling errors from both teams. It may have been nerves but the rain didn't help, the two sides struggling to master the slippery conditions.
The 14 handling errors of Ireland compared with five for the U.S. was one compelling reason why the Irish struggled to dominate.
Ireland 22 (Tommy Bowe 2, Rory Best tries; Jonathan Sexton penalty, conversion; Ronan O'Gara conversion) def. United States 10 (Paul Emerick try; James Paterson penalty, conversion). HT: 10-0.