A talismanic presence at Camp Nou has endured an injury-hit opening to the 2019-20 campaign, with fitness issues restricting him to just four appearances.
The most recent of those saw him take to the field for a European encounter in Catalunya.
Barca fell behind on home soil inside two minutes, as Lautaro Martinez broke the deadlock, but hit back through a double from Luis Suarez to claim three welcome points.
Messi provided the assist for what proved to be the match-winner, with Ter Stegen delighted to have the five-time Ballon d’Or winner back and delivering moments of inspiration.
“It always makes us happy having him on the pitch and giving the best he can: passes, assists, goals,” the Germany international goalkeeper said of his skipper.
“We're happy that he played 90 minutes. He couldn't [before] due to injury, but we hope this won't happen again. It's always easier with him.”
While Messi played an important role against Inter, it was Suarez who stole the headlines.
Ter Stegen is pleased for the Uruguayan striker, saying: “He shuts a lot of people up.
“He's always focused and gives his best. And he always fights. We know who we have up front. He's always there to score goals.”
Ernesto Valverde’s side were not at their best against Inter, but did enough to collect a first continental victory of the campaign.
“We scored two good goals. We made some mistakes, but these things happen,” Ter Stegen added.
“They also have lots of quality and it was us who came out on top.
“Although we did suffer a lot, this is also part of football.
“The opposition know how to play football, and quite well.”
Inter posed plenty of threat at Camp Nou, with Ter Stegen required to pull off a crucial second half save to prevent Martinez from grabbing his second of the game.
“I'm trying to improve each day. If it goes like this, perfect; I'm happy to be there when needed,” said the highly-rated 27-year-old shot-stopper.
“I'm one of many and each one wants to show that we're there to fight for everything.
“Scoring is more difficult than making saves. I'm giving my best.”