With the U.S. trailing 0-2 after world number 175 James Ward had completed a shock win over Sam Querrey on Friday, the Bryan brothers lived up to expectations in front of jubilant fans at Petco Park as they triumphed in just under two hours.
In dazzling sunshine on the red clay surface set up at the home of Major League Baseball's San Diego Padres, the Bryans won 12 of the first 15 points to race 3-0 up before winning the opening set on a Fleming double fault after just 24 minutes.
The Americans maintained their commanding form to go two sets up but the British duo began to gel and broke Bob Bryan's serve in the seventh game of the third before an Inglot ace clinched the set and took the match into a fourth.
However, the Bryans regained control when they broke Inglot's serve in the second game, and again in the sixth, before sealing victory when Mike served out, Bob putting away the winning point with a forehand smash at the net.
"We just stayed solid," a beaming Bob Bryan said in a courtside interview after he and his brother had earned their 21st Davis Cup win together.
"We want to thank all the crowd for staying and keeping us fired up. We can't say enough. This is such a beautiful venue and a full house today pulling us through. It was a really cool atmosphere."
His brother Mike spoke about their love for the team competition.
"Days like this make it so much fun to keep playing, man," he said. "We love playing Davis Cup, we love playing for our country. It was a blast to play out here today.
"We still believe. I think we can come out here tomorrow and get one on the board and see what happens in the fifth match."
Britain will be favoured to secure their first victory over the Americans in the competition since 1935 when Wimbledon champion Andy Murray takes on 49th-ranked Querrey in the first reverse singles match on Sunday.
World number six Murray has a 5-1 career record against Querrey, his only loss coming on the hard courts of Los Angeles in 2010. They have never met before on clay.
The 79th-ranked Donald Young is then scheduled to play against Ward in the second reverse singles.