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."
Andretti along with powertrain supplier Porsche were the early pacesetters in the 2022-23 campaign – the first one of the Gen3 era – before Jaguar and its customer team Envision proved the combinations to beat by the end of the season.
Both Envision and Andretti beat their respective factory outfits in the final teams' standings, the former claiming the title, and when asked if this scenario would repeat itself this year, Dennis said: "It will be close, if it does!
"We've all got the same software, almost the same powertrain, and both teams are working at an incredibly high level. I don't think it will be a walkover by any means, but whether we beat the Porsche team or the Jaguar team, we just want to beat everyone."
Any chance of taking a first teams' title will require better performance from Andretti's second car, with Andre Lotterer scoring just 23 points last season and Dennis commenting after winning the world title that he wanted a team-mate pushing him to his "highest level".
Frenchman Norman Nato has been hired for the upcoming season, which gets underway in Mexico City on 13 January, having impressed in the final races of 2023 with Nissan.
"I think we can definitely have more points than last season," added Dennis. "There's obviously a big effort from everyone to try and get that sister side of the garage working better. From testing so far, it's gone extremely well, he's performed extremely fast."
