Cameron Norrie produced a stunning fightback to beat Roberto Bautista Agut in Great Britain's Davis Cup tie with Spain, while defending champions France are level with Netherlands.
After Liam Broady was beaten in straight sets by Albert Ramos Vinolas in Marbella, Britain - champions in 2015 - looked set to fall 2-0 behind as Bautista Agut forged a two-set lead.
But Norrie, ranked 114 in the world, produced an incredible turnaround against world number 23 Bautista Agut, rattling off three successive sets to win his first match on clay outside of the futures circuit 4-6 3-6 6-3 6-2 6-2.
He said afterwards: "In the fifth set I went to serve and there was an eruption of noise and I thought, this is an incredible experience. I'm so happy. Best day of my tennis career, 100 per cent.
"I couldn't be happier with my performance. At the end I just tried to take it point by point and focus on my routines. I was just the better competitor and that showed. It was an incredible match - I'm going to struggle to sleep tonight for sure."
Richard Gasquet restored parity for France after Thiemo de Bakker surprised Adrian Mannarino, beating Robin Haase 6-4 7-6 (7-3) 3-6 7-5.
The United States needed over six hours to move into a 2-0 lead over Serbia, Sam Querrey overcoming Laslo Djere 6-7 (4-7) 6-2 7-5 6-4 in three hours and two minutes before John Isner ground out a 6-4 6-7 (7-9) 6-3 3-6 7-6 (7-4) triumph over Dusan Lajovic after three hours and 15 minutes.
Alexander Zverev needed nearly four hours to defeat teenager Alex de Minaur 7-5 4-6 4-6 6-3 7-6 (7-4) before Nick Kyrgios redressed the balance with a 6-4 6-4 6-4 victory over Jan-Lennard Struff in Australia's tie with Germany.
The ties between Japan and Italy and Croatia and Canada are also level, while Kazakhstan and Belgium hold 2-0 leads over Switzerland and Hungary respectively.