The five-time world champion crossed the line in second place, 21 seconds behind teammate Valtteri Bottas. The Briton was beaten off the line by Bottas who started alongside him on the front row.
After the chequered flag, Mercedes revealed that Hamilton was missing a "chunk" from his floor.
“We have discovered damage to Lewis' floor at the region of the left-rear tyre seal (in front of the rear tyre) which will have exacerbated the challenges he had with the car balance,” confirmed a Mercedes spokesperson.
“A chunk of the floor is missing, not sure how or why at this stage.”
Speaking after the race, Hamilton admitted that he had an idea on where the pace went, adding that he would have to go through it with his engineers.
“I do have some ideas [on the pace loss] but I’ll wait to go over it with my engineers.
“Naturally it’s a little bit frustrating to lose position at the start when you’ve had a good weekend up until that point but that is how the game goes. I’ll just train and work hard to come back next time.”