The United States and Russia both trailed 2-0 in their Davis Cup World Group quarterfinals on Friday.
Ivo Karlovic and Marin Cilic won five-set marathons at home to put Croatia 2-0 ahead of 32-time champions United States.
Karlovic recovered to put hosts Croatia 1-0 up after scraping past James Blake -7 (5-7), 4-6, 6-3,
7-6 (7-3), 7-5 after three hours and 38 minutes in front of a partisan crowd in Porec.
Cilic later put a perfect ending to the day for Croatia by sinking Mardy Fish 4-6, 6-3, 6-7 (2-7), 6-1, 8-6.
Israel are within sight of a first semifinal at a major sporting event, with Dudi Sela and Harel Levy emerging heroes in front of more than 10,000 fans in Tel Aviv, the biggest crowd to watch a tennis match in the country.
Sela came from a set down to beat Mikhail Youzhny 3-6, 6-1, 6-0, 7-5 after Levy stunned Igor Andreev 6-4, 6-2, 4-6, 6-2.
Last year's runners-up Argentina fell behind to Czech Republic in Ostrava when Tomas Berdych recovered to beat Juan Monaco in five sets but Juan Martin Del Potro levelled the tie at 1-1 with a comfortable straight sets win over Ivo Minar.
The Spanish, missing the injured Rafael Nadal and David Ferrer, had Fernando Verdasco to thank for putting them in front against Germany, although the world number nine had to come back from 2-1 down against Davis Cup newcomer Andreas Beck.
In sweltering conditions on the clay at the bull ring in Marbella, an efficient Philipp Kohlschreiber then brushed aside Tommy Robredo in straight sets to make it 1-1.
The winner of the Spain-Germany tie will play Israel or Russia for a place in the final with the U.S. or Croatia taking on Argentina or the Czech Republic.