George Russell says Williams was “absolutely nowhere” in Mexico while he exacerbated his own plight by knocking out his drinks tube.
Russell surged from 16th on the grid up to ninth on the opening lap as he took advantage of a chaotic first few corners at the Autodromo Hermanos Rodriguez.
But Russell slid through the midfield order across the remainder of the race and eventually classified as a twice-lapped 15th.
“It was probably the toughest afternoon we’ve had all season,” said Russell.
“It was really, really difficult. I thought we were on for a good result after the start, getting up to ninth, then we were just nowhere, absolutely nowhere, one of those days.
“I thought I’d damaged the front wing so when I thought it was safe to do so I slightly loosened my belts and just peered over the top [of the car].
“In doing so it yanked the drinks tube out so I lost the drinks tube under the Safety Car.”
Williams team-mate Nicholas Latifi followed Russell home in 16th spot.
“Unfortunately, my race came undone at the start,” said Latifi.
“I’ll have to watch the video back to see what happened in that first lap. I thought I was going to come out of the first few corners gaining a couple of positions from the cars going off, but I stayed on track to avoid them and ended up losing out quite a bit.
“After that, with the pace we had, it was just a race of blue flags. It was an afternoon to forget but now it’s onwards to Brazil.”