Katie Swan inspired Great Britain to an emphatic 3-0 victory over South Africa in the Fed Cup on Thursday.
Swan, 16 - who became Britain's youngest-ever Fed Cup player following Johanna Konta's withdrawal - recorded a straight-sets victory over Ilze Hattingh.
Heather Watson then followed Swan's triumph with another win for Judy Murray's squad before the doubles team of Jocelyn Rae and Anna Smith completed the whitewash.
Britain will now face Georgia in their final tie on Friday with victory likely to set up a tie against Belgium as they bid to secure a World Group II play-off in April.
Swan, ranked 524th in the world, earned a late call-up to Murray's team after Konta pulled out through injury.
But the teenager, who reached the Australian Open girls' final in 2015, took only 55 minutes to dispatch her opponent 6-3 6-0.
"I was really excited to play but I was also a bit nervous, which was showing in the beginning, but I managed to relax after a few games and I started playing really well," Swan told the Fed Cup website.
"It's just amazing to get to play for your country - for me it's the best thing in tennis representing your country.
"British tennis is doing amazing. We have the Davis Cup boys who just won and obviously Jo and Andy Murray and Jamie Murray doing so well in Australia. It's inspired the whole team."
Watson, who fell at the first hurdle in the Australian Open last month, beat world number 317 Chanel Simmonds 6-3 6-3 before Rae and Smith also won in straight sets.