It means that the Frenchman has now failed to score points in his last two races, having only missed out on the top ten in three of the previous 12.
Ocon lost part of his front wing in the collision with Renault’s Sainz and was forced to pit for a new front wing, which relegated him all the way to last position.
In a race where his Mexican team mate Sergio Perez retired in his home race, Ocon was unable to keep the pressure on McLaren in the Constructors’ Championship as Stoffel Vandoorne finished eighth, ending his barren run.
Ocon was clearly frustrated with himself after the race and said: “This has been probably the worst race of my whole Formula One career so far, nothing went our way and it’s just been a terrible afternoon.
“I made a very good start, managed to pass the two Saubers on the run down to Turn 1, but that’s pretty much the only positive to take from today.
I went alongside Carlos in Turn 3 but I saw he was going to turn in.
“I braked to avoid a collision, but we still made contact and it broke my front wing. I had to pit at the end of the first lap and my race was effectively over.”
There are just two races left until Ocon leaves Force India, with Lance Stroll set to take his seat for 2019.