Australia defeated the United States and Argentina swept past the Netherlands as the blue group got underway at the World Team Cup on Monday.
Mark Philippoussis and Lleyton Hewitt were victorious in their singles rubbers for Australia before Wayne Arthurs and Paul Hanley lost the final dead doubles rubber.
Argentina whitewashed the Netherlands with Mariano Zabaleta and Lucas Arnold adding victory in the end-of-day doubles rubber to wins for Gaston Gaudio and Juan Ignacio Chela in the singles.
Philippoussis' 6-7, 6-3, 7-6 win over Vince Spadea was his first in eight matches and he paid tribute to the unity in the Australian team for helping him to end his miserable run.
"It's good to meet up as a team and I think we enjoy each other's company," said Philippoussis. "It helps you relax and you are able to concentrate on your game.
"It was a very important win for me and it was good that I could come out on top in a tight match. This is no warm-up for the French Open. We're all very focused on this tournament at the moment."
Philippoussis saved a match point in beating Spadea before Hewitt eased past Robby Ginepri 7-5, 6-7, 6-4. Bob and Mike Bryan beat Arthurs and Hanley 6-2, 6-4 in the doubles.
Gaudio, a late replacement for stomach-bug victim Agustin Calleri, came from a set down to defeat 2003 French Open finalist Martin Verkerk 2-6, 6-2, 6-4.
Chela built on Gaudio's win to close out the tie for Argentina with a 6-3, 5-7, 7-5 victory over Sjeng Schalken in a scintillating match that captivated a neutral German crowd.
Argentina completed their win in style when Zabaleta and Arnold beat Verkerk and John van Lottum 3-6, 6-3, 6-3.
"It was not how we wanted to begin the tournament but I think all games were very close," said Verkerk. "I think the result could have been very different."
The red group will resume tomorrow with opening day winners Germany and Chile taking on Czech Republic and Spain respectively.