While the Silver Arrows will start the race on medium tyres, Leclerc will have a slight advantage from third on the soft compound.
However, Leclerc predicts Mercedes dominance in the race if he is unable to make a move on Hamilton or Bottas off the line.
"If we look at the Friday race simulations I think it's going to be very difficult to fight, [Hamilton's] race run was very strong," Leclerc said.
"Red Bull seems to be very quick also in the race run so it's going to be tricky. If we manage to gain some positions at the start, it's a track where it's quite hard to overtake so then we have some chances to keep them.
"But if not I guess it's going to be very difficult to fight with them."
Sixth on the grid, Vettel will start behind both Red Bulls for the second race in succession and expects a tough time clearing Max Verstappen and a resurgent Pierre Gasly, who has showed good pace all weekend so far.
"In the race, normally it's fine," he told Sky Sports. "The Mercs will be very quick but I think race-pace looks fine. It has been through the whole year more or less.
"It will be a tough battle I guess between us and the Red Bulls."
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