The Briton clinched his maiden Formula E crown last season with Andretti, taking two wins and a further nine podiums to seal the championship on home soil, having bounced back from a low-key start in pre-season testing and a four-race point-less streak.
It marked the 28-year-old's third campaign at Andretti, having joined the outfit when it was BMW's factory team in the series, and he's been impressed with the progress that has been made since then.
"I've been with them from the start," he said. "The team has developed so much since the BMW days, and we've brought in some really good personnel along those years.
"I feel like we're performing at an incredibly high level, higher than any other team, I would say."
Dennis has shown faith in Andretti by signing multi-year deals in both August 2022 and December 2023 as the American squad acted fast to secure his services beyond the end of the 2025 campaign, with Dennis admitting other teams expressed some interest in signing him.
"I'd be lying if [I said] there wasn't, you know," he said. "Becoming champion, obviously, generally generates a lot of interest.
"But to be honest, I was very happy with Andretti. I was already contracted to them this year anyway, even without the extension. It wasn't like I was gonna be going anywhere after Season 9. It just felt right to continue the partnership with them.
"For me, there was no real tough decision to make."
Source: Autosport