Venus Williams and CoCo Vandeweghe won the opening singles matches to give holders the United States a commanding 2-0 lead in their Fed Cup World Group opener against the Netherlands in Asheville, North Carolina on Saturday.
Williams, with younger sister Serena watching on from the sidelines after being selected for the team, struck first with a 6-1, 6-4 victory over Arantxa Rus on the indoor hard court.
After racing through the opening set, Williams was made to work in the second where the first five games all ended in service breaks. Williams finally saved a break point in the sixth game and held serve for the first time in the second set.
"It's never easy and it's always a challenge," Williams said after beating her 124th-ranked opponent. "On paper, today I looked like I should win but it was a battle and I'm glad to get through that."
With the win, Williams joined Billie Jean King, Chris Evert and Lindsay Davenport as the only American women to win 20 or more Fed Cup singles matches.
World number 17 Vandeweghe battled back for a 4-6, 7-6(6), 6-3 victory over world number 108 Richel Hogenkamp to put the Americans one win away from the April 21-22 semi-finals.
Hogenkamp won four consecutive games to take the opener but Vandeweghe levelled the match with an ace on her fourth set point, triggering a massive fist pump and show of emotion that few expected from what initially appeared to be a mismatch.
Vandeweghe charged home in the decisive set to give her side a comfortable lead heading into Sunday's reverse singles and doubles closer.
Serena Williams, who has not played a competitive match since she won the Australian Open title last year, will team up with Lauren Davis in a doubles match that will be played even if the U.S. clinch the tie earlier.
Elsewhere, the Czech Republic, winners in five of the last seven years, ended day one of their tie in Prague against Switzerland 2-0 ahead after Petra Kvitova beat Viktorija Golubic in three sets before Barbara Strycova eased past Belinda Bencic.
Belarus were locked at 1-1 with Germany in Minsk while hosts France and Belgium were also level going into Sunday's action.
Elise Mertens, an Australian Open semi-finalist last month, gave Belgium the lead with a 6-2 6-1 victory over Pauline Parmentier but Kristina Mladenovic beat Kirsten Flipkens 6-2 6-4.
Wawrinka upbeat after Sofia defeat
Three-time Grand Slam champion Stanislas Wawrinka, on his way back after undergoing knee surgery last year, was in upbeat mood despite losing in the Sofia Open semi-finals on Saturday.
The Swiss believes he needs more time to reach full fitness after going down 7-6(6), 6-4 to Bosnia’s Mirza Basic in his fifth competitive match in seven months.
Wawrinka was knocked out in the second round of the Australian Open last month, losing to unheralded American Tennys Sandgren in three sets.
“It would have been great to win one more match but I need to take the positives from this week,” the 32-year-old told a news conference.
“It was positive to have three matches in a row and win two matches. For sure it costs me more energy to win matches, since I am not used to play matches, but that is what I have to do to get back to my level.”
Wawrinka, who dropped to 15th in the world rankings in his absence from the tour, said he did not feel any pain during the tournament in Bulgaria.
“My knee's getting better,” he said. "I am really happy and positive after the surgery, it has been six months until now and everything is going really well. I think I am doing everything possible to get back to what I want to be."
Wawrinka, however, remains cautious about his prospects of a long run.
“I am moving well, I am playing well, but it is part of a process… to play more matches, to become more confident,” he said.
“There are a lot of things that you have to put together. It is not only about fitness, not only about tennis. It is also about being more relaxed while you play.”
Wawrinka will play next week in Rotterdam where he won his last indoor title in 2015.
“Tomorrow I am travelling and will try to practise there to prepare for my first match and to keep improving.”
Pouille claims fifth ATP title in Montpellier
Lucas Pouille won his fifth ATP title by beating Richard Gasquet 7-6(2) 6-4 in an all French final at the Open Sud de France in Montpellier on Sunday.
The second seed was solid on serve throughout, not facing a single break point as he prevailed on his fourth match point for his first title of the year.
It was Gasquet's sixth consecutive final in Montpellier, but his second defeat in a row after he was beaten by Germany's Alexander Zverev last year.
Gasquet won the title here in 2013, 2015 and 2016.
Gasquet saved three break points and forced a tiebreak in the first set. Pouille won two points on his opponent's first serve to win it 7-2 and take the lead.
Pouille broke decisively in the seventh game of the second set and did not look back.