Fed Cup debutant Ashley Harkleroad sealed victory for the United States over Germany in their world group first-round tie with a 6-4, 7-5 defeat of teenager Sabine Lisicki on Monday.
Harkleroad, 22, came from 4-1 down in a second set littered with unforced errors to give the hosts an unbeatable 3-1 lead at the La Jolla Beach & Tennis Club.
Lindsay Davenport and Lisa Raymond wrapped up the tie 4-1 by outplaying Tatjana Malek and Anna-Lena Groenefeld 6-2, 6-0 in the dead doubles rubber.
The US advanced to an away semi-final on April 26-27 against defending champions Russia.
Earlier on Monday, Davenport swept aside Germany's Julia Goerges 6-1, 6-2 in the first reverse singles match after the teams began the day locked at 1-1.
Harkleroad, who capped a memorable debut in the team competition with successive singles victories, traded early breaks of serve with Lisicki.
A tight opening set then went with serve until the ninth game when the German was broken after netting a forehand.
Leading 5-4, world number 74 Harkleroad held off a spirited display by Lisicki in a protracted 10th game before converting a third set point when her opponent hit a forehand long.
Lisicki, ranked 129th, took early control of the second set, breaking the American and forging 4-1 ahead.
The Fed Cup rookies exchanged breaks of serve in the seventh and eighth games before Harkleroad tightened her grip.
RASPING WINNER
She broke Lisicki in the ninth with a rasping forehand winner, held in the 10th, broke again in the 11th and clinched victory when the German netted a backhand service return.
"I'm just proud of myself and super excited at the way that I played and handled my nerves at the end," a beaming Harkleroad told reporters after completing a victory lap around the court with a US flag raised in one hand.
"I felt like my arm weighed a hundred pounds. I was a little bit nervous but I always had a plan today."
Davenport, 31, got the home team back on track by outclassing Fed Cup debutant Goerges.
The American former world number one, who suffered a shock defeat in Saturday's opening singles encounters, broke the German twice in the opening set to take control.
The 19-year-old German, struggling with her serve, was again broken in the first, third and fifth games of the second before Davenport surprisingly lost the sixth when serving for the match.
Goerges held serve before Davenport, ranked 44th after returning to the court last September following an 11-month absence to have a baby, powered down two aces to wrap up a one-sided win.
"I played better today although I still have some ways to go," a smiling Davenport said. "Most importantly I got a victory to put the team up.
"It was great to see Ashley do so well. In some ways, it makes the win even more exciting. She really carried the team and played great."