Andy Murray and James Ward have put Great Britain on the verge of the Davis Cup quarter-finals in San Diego.
Wimbledon and Olympic champion Murray was expected to beat the USA's Donald Young and secured the opening rubber 6-1, 6-2, 6-3.
But world number 175 Ward - who is proving an impressive performer in the Davis Cup - took five sets to beat 45th ranked Sam Querrey 1-6, 7-6, 3-6, 6-4, 6-1.
Murray and Colin Fleming could now wrap up the tie against world number one pairing Bob and Mike Bryan in the doubles.
But team captain Leon Smith hinted he may rest Murray in the knowledge a win over Querrey in Sunday's reverse singles rubbers would be enough to claim a first World Group win since 1986.
Smith had flirted with the idea of dropping Ward in favour of rising star Kyle Edmund, thought a better performer on clay.
But Ward beat the 19-year old in a practice match and his record of eight wins in 13 singles matches, including an impressive victory over Russia's Dmitry Tursunov last year, rightly swayed the decision.
"That's why he got picked at the end of the day," said Smith.
"I don't want to take any credit, I just sit there. It's down to James.
"He kept believing in himself and we just talked about being the aggressor, being the boss. He won a lot of the points when he got Querrey on the back foot. He's been brave, he's been courageous and he deserved it."
Murray simply had too much firepower for world number 79 Young, who was drafted in as a late replacement for John Isner, the world number 13.
"It's important that we got off to a good start," he said.
"The court is still pretty slippery but it's been raining, it's colder, there's a lot of cloud cover, so it's playing a bit slower. The conditions being like this helped.
"We'll have to see about the doubles. I will speak to the captain and the rest of the team and see what the best way forward is."
© Sportsbeat 2014