Adrian Newey has admitted that Red Bull do not have a strong chance of winning this weekend's Monaco Grand Prix.
Last year, only a pit bungle cost Daniel Ricciardo victory on the famous streets.
"Last year we had a good chassis," Red Bull's part-time technical boss Newey told Brazil's Globo, "so at Monaco, where you rely less on the engine, we could shine.
"But this year we do not have the best chassis, so we will not have the same opportunity as last year.
"I think we have to improve between now and Singapore, and use that as our next chance."
Red Bull are 81 points behind second-placed Ferrari in the constructors' championship heading into the race.