Serbia's bid to reclaim the Davis Cup crown they surrendered to Spain a year ago started positively as they eased into a 1-0 lead over Sweden.
Janko Tipsarevic was barely troubled as he cantered to a three-set win, beating tournament debutant Filip Prpic 6-3 6-3 6-4 in two hours and five minutes.
Also taking 1-0 lead were Argentina, with Juan Monaco impressing as he got the better of Germany's Philipp Petzschner in Bamberg.
He dropped nine games on his way to the win, running out a 6-3 6-3 6-3 winner as his erratic host made 47 unforced errors.
In Hyogo, Japan and Croatia were tied at one rubber each after the first day's play.
Go Soeda gave the hosts the perfect start, coming from two sets down to beat Ivan Dodig 6-7 (3/7) 3-6 6-4 6-3 7-5 in a four-hour marathon.
But the big-serving Ivo Karlovic levelled things up in under half the time, sending down 18 aces in a 6-4 6-4 6-3 win over Kei Nishikori.
Those present were still talking about Soeda's epic win, though, and he responded by saying: "I think it was my biggest win ever."
