The reigning Formula E champion took victory by more than 13 seconds in the first of two races in Saudi Arabia, but never featured in the sequel.
This was after the Andretti driver failed to make it through his qualifying group when a red flag was deployed on his final effort and he was forced to start 14th for the 36-lap race in Diriyah.
Despite having strong pace the Briton failed to make progress, and was eventually being classified outside the points with a lack of one-lap pace a growing concern.
“The red flag didn’t ruin our weekend to be honest, we weren’t making the duels even if I finished that lap, that wasn’t the issue,” Dennis told Autosport.
“Just pure pace over one lap was nowhere, but we proved in the race that we were quick again.
“Fastest lap and definitely one of the quickest cars in the race, but just no pace over one lap.
“It’s becoming a bit of a trend, sometimes we can drag a lap out of it and get it into the top five but it’s a real difficult task.”
Dennis currently sits fourth in the drivers’ standings, 29 points behind championship leader Nick Cassidy after the Jaguar driver took victory on Saturday.
Dennis admitted his victory in the prequel “was more relief” after a less than ideal start to his title defence having only finishing ninth in the season-opening Mexico City E-Prix.
“I’m just glad I got some big points because otherwise we would have had a pretty rough start to the year,” said Dennis.
“I’m just shocked why we were so bad today, basically over qualifying but then so good in the race again.
“Lots of figures to look into and understand why over one lap this track when it gripped up was really tough for us.”
Dennis finished 10th on-the-road and in the final point scoring position in Diriyah, but he was handed a five-second penalty post-race for overtaking under yellow flags.
This occurred after Mitch Evans took his Attack Mode activation on the exit of Turn 18, where yellow flags were present after Jehan Daruvala had come to a stop in the run-off area with a brake problem.
“Mitch took Attack Mode and instead of stopping and waiting for him I just continued on my normal racing line,” said Dennis, who also lost his point for fastest lap as a result of being outside the top 10.
“It’s difficult for the officials to judge, it’s difficult for me to judge.
“Thankfully I had no one behind so I could have stopped, but if it happened to the guys in front who were battling, it would have been an absolute disaster because they would have had to stop which would have caused a big incident.
“But for me and Mitch we were at the back of that train. It was one of those races where everything sort of went against you.”
