The Chinese racer managed his best F1 qualifying effort to date on Saturday to start fifth but was swamped by the pack after a sluggish getaway, before running into the back of Daniel Ricciardo's AlphaTauri under braking for Turn 1.
Ricciardo then inadvertently punted Esteban Ocon into Pierre Gasly, with both Alpine cars eliminated as a result.
Zhou copped front wing damage in the impact and also incurred a five-second penalty from the stewards, who decreed that he "simply did not slow down enough when approaching the corner, resulting in an unnecessary collision".
After finishing a lapped 16th, Zhou said Alfa Romeo would look into his startline issue.
"I have no idea, I need to have a look," Zhou replied when asked about his start problem. "I was holding the revs before the four lights and then I just lost all the response from the throttle, so I started basically [with] zero throttle.
"Really disappointed because I think it could be really good at that point at the start."
He later added: "We need to see more in detail what happens there because this is strange, it never happens before at all. I tried to recover before the five lights, tried to go full throttle, but nothing was happening unfortunately, so I had to do a pull-away.
"So my start was actually a pull-away, it wasn't actually a start. That's why you saw my car wasn't moving."
Asked by Motorsport.com to explain his Turn 1 incident, Zhou said: "I was trying to obviously brake as late as I could to try to gain some positions back, but then partly to the dirty air of the cars ahead unfortunately I locked up into them.
"So not what I wanted, but the race was pretty much over after the line for me."
Zhou's start woe also delayed team-mate Valtteri Bottas, who lost momentum jinking around him and dropped from seventh to 12th as a result. The Finn finished in the same position after he was unable to pass the Williams of Alex Albon in the final stint.
Bottas pitted early to try and recover lost ground, following Lance Stroll's Aston Martin into the pits on lap nine. The two diverged on their second stops, Bottas pitting six laps later, but he rejoined behind Albon and even with DRS couldn't make it by.
"I felt like I lost like half a second per lap [stuck behind Albon]," Bottas explained. "It was just not quite enough to attack or get by and they were also really quick on the straight like normal.
"Unfortunately, we lost all this time, it's hard to catch and be fighting with Stroll in the end. It's always tough when you get stuck behind a Williams, it's tough to get by."
Bottas admitted he was mystified by Alfa's struggles in race trim after its strong qualifying showing at a track Alfa believes is "one of the strongest races for our car this year".
"Somehow on a single lap, at this track it's working," he said. "But as soon as the tyres, they start to drop in the race, we start to slide more.
"I don't know - I've no idea."
Bottas's comments were echoed by Zhou, who felt "our one lap pace was more close to the top guys than racecraft".
Asked by Motorsport.com where the car was weaker on Sunday, Zhou replied "just in general grip".
Additional reporting by Adam Copper and Matt Kew
