Late replacement Philipp Petzschner beat Ivo Karlovic of Croatia 6-4, 7-6 (3), 7-6 (5) to give Germany a 3-2 win to advance to the quarterfinals of the Davis Cup.
Petzschner replaced Florian Mayer in the decisive first-round match, breaking Karlovic decisively in the opening game of the first set with the Croat also struggling on serve during the two tiebreakers.
''Petzschner played extremely good doubles on Saturday and hit some great returns on Karlovic' serve,'' Germany captain Patrik Kuhnen said. ''I felt Croatia might pick Karlovic today after Ivan Dodig played two five-setters in two days.''
Germany will play either France or Austria in July.
Earlier, Marin Cilic drew Croatia level by beating Philipp Kohlschreiber 6-2, 6-3, 7-6 (6).
Karlovic lost two break points at 2-1 in the second set. The German broke early in the third, but Croat responded immediately and had three break points at 5-5.
''The feeling was great,'' Petzschner said. ''I'm happy for myself and for the team. It was tough tie with tough matches.''
Karlovic, who set the world's fastest serve in professional tennis at 251 kph (156 mph) during the doubles match on Saturday, said Petzschner was too good.
''He started great, found the rhythm on my returns. He played exactly as I did not want him to play,'' Karlovic said. ''He played some unbelievable shots on my first serves.''
Karlovic broke Andy Roddick's record of 249 kph (155 mph) for the fastest serve, set in the Davis Cup series against Belarus in Charleston in 2004 while playing against Vladimir Voltchkov.
Despite his booming serve, Karlovic and Ivan Dodig lost the doubles to Christopher Kas and Petzschner in five sets Saturday.
Cilic converted five of 12 break points and dropped serve once, while leading 2-0 in the third set.
''I played a lot of matches against Kohlschreiber and knew exactly what I had to do,'' Cilic said. ''I served extremely well, played aggressive. It was very important to start well because there was some pressure on me, knowing that if I lose there won't be any way back.''
