Sergio Perez has admitted that Force India's 2017 car is currently among the very slowest on the grid.
With their small budget, the Silverstone-based team finished an admirable fourth overall last year.
The team then signed up a new sponsor and painted their car pink for 2017, but Mexican driver Perez admits that Force India are currently struggling.
"We're missing speed both on one lap and in race pace," he said ahead of the Chinese Grand Prix.
"We are currently the seventh or eighth fastest team in the field."
It is known already that, after Perez and teammate Esteban Ocon bulked up over the winter, Force India asked them to then lose that weight to help the team's competitiveness.
Germany's Auto Motor und Sport reported that the big update to fix the current problems - including smaller sidepods - will not be ready until Montreal in June.
Until then, Perez said: "We have to take advantage of every opportunity that is offered to us. Just like in Australia. This was a great weekend for us with a result we did not expect."
Perez and Ocon placed seventh and 10th respectively in Melbourne.
