Dennis was running just outside the top 10 and was shadowing points leader Pascal Wehrlein after both title protagonists qualified down the order for Saturday’s race.
Heading into Turn 1 just before half distance, Ticktum’s NIO 333 machine made heavy contact with the rear of Dennis’ Andretti car which caused significant damage to the latter.
This became evident into the right-hander of Turn 3, when Dennis lost the rear under braking and took to the inside of Wehrlein, hitting the Porsche machine, before stopping his own car on track which resulted in a safety car.
Wehrlein was able to continue despite suffering damage in the contact with Dennis, and finished seventh, while Ticktum finished 14th.
“Two races now just driving my own race and then some plonker 100 metres behind me forgets to brake and smashes into me,” said Dennis, who now sits 24 points behind Wehrlein in the standings.
“It’s typical, I don’t know what else I can do. I don’t know what he was thinking.
“I’ve seen the onboard and it’s like he’s in his own little world. I’m pretty annoyed with Dan.
“It hurts a lot. Myself and the team spend a week doing the full preparation away from home and all the work behind the scenes before that just for some geezer to forget to brake. It’s ridiculous.”
Ticktum later accepted responsibility for the collision.
“It just didn’t stop,” he said.
“This concrete surface which was laid before the race weekend - when there’s a bit of rubber on it it’s okay, but if you’re offline...
“I mean, I was braking even earlier than the car I was trying to overtake and it just didn’t stop.
“Obviously combined with the fact there’s more dirt offline... I’ve never known anything like that in my whole racing career, it just did not stop.
“Of course if I see him [Dennis] I’ll apologise, because obviously I didn’t mean to do it at all."
Wehrlein said “maybe a P4” would have been possible but for the collision.
“I really suffered with balance at the end of the race, the whole floor was missing on the right side,” he said.
“I just destroyed my rear tyres because of that.
“I think how the race went, more was not possible but without that contact I think a bit more was possible.”
