Dennis enjoyed a strong showing in the Indonesian double-header, qualifying on the front row for the first time since the season opener in Mexico City before going on to finish second in each of the two races.
This made him the second-highest points-scorer over the course of the weekend, only behind Race 2 winner Maximilian Guenther of Maserati.
With five races remaining in Formula E's first Gen3 season, Dennis finds himself right behind Porsche's Pascal Wehrlein in the standings, having trailed erstwhile leader Nick Cassidy by 25 points going into Jakarta.
The British driver hailed Andretti for delivering a big step-up in one lap performance in Indonesia, allowing him to qualify up front and score the big points he needed in order to strengthen his bid for a maiden title.
"Honestly, just a big thanks to the team," said Dennis. "That's the biggest thing, [just] how much effort we put in from here to the previous races over qualifying.
"It's really shown and it's really paid off because qualifying in the past few races hasn't mattered all that much but this weekend it's been crucial.
"It really helps to bring my championship back alive. We will see whatever happens in Portland. It's completely different from how most FE circuits are, very fast, very flowing.
"There will be lots of overtaking, similar to Berlin and yeah, just some time off now before we go again in a few weeks."
Another driver who was an outside bet for the Formula E title coming to Jakarta was Jaguar's Mitch Evans, who had lost a big chunk of points in Hyderabad when his team-mate Sam Bird took him out of the race.
Jaguar was unusually off the pace in Jakarta, with neither the factory team nor customer squad Envision featuring at the front, with Evans' misery compounded by another crash with Bird in the opening race.
But he bounced back from the incident to finish on the podium behind Guenther and Dennis in the second leg of the round, keeping a train of cars behind on the tight confines of the Jakarta track.
Evans now faces a 25-point deficit in the standings, with Wehrlein, Dennis and Envision's Nick Cassidy all in front of him, but the Kiwi isn't ruling himself out of the title fight yet.
Asked if he felt his title challenge was still on, Evans replied: "For sure. There are still five races left, so loads of points.
"It's a shame we didn't execute a better weekend. Also, could have been worse off the back of Saturday's [race] in terms of pace, [but] I will look at the bright side. We are 100% still on this.
"I'm sure when we go back to other tracks we should be more competitive and back to our usual pace. So hopefully this was a bit of a one-off.
"We soon need to work out why, because we will be coming back next year etc. Strange but grateful for the points."
