After a blistering first set and an early break by Team World in the second, the European duo squandered their only two break chances to hand John McEnroe's team the two points.
Shelton had earlier been beaten 6-4, 6-4 by Carlos Alcaraz in the singles as the Spaniard levelled the overall score to 4-4 following American Frances Tiafoe's 3-6, 6-4, 10-5 comeback win over Russian Daniil Medvedev in Saturday's opening clash.
"I love playing here, I love the format, singles and doubles. I couldn't get it done in the singles but I wanted to come here tonight and redeemed myself," Shelton said.
"Alejandro put me on his back a little bit and we were able to get it done, so I'm really happy and thank you everyone for staying late."
Prior to the doubles match, American Taylor Fritz put Team World ahead as he outclassed German Alexander Zverev 6-4, 7-5.
The US Open finalist rallied from a 2-4 deficit in the second set to seal his third victory over the world number two.
First-day victories at the three-day team contest at Berlin's Uber Arena are worth one point apiece, with two points being awarded for wins on the second day, and three points each on the third and final day on Sunday.
