Toto admits we don't head into the weekend as the leading contender for Monaco and is anticipating an intense run of races for the team, as the European season kicks in.
"We don't head into the weekend as favourites - they are Red Bull and Ferrari," he said. "Red Bull are strong in the slow-speed corners and where straight-line speed is less important, while Ferrari dominated last year.
"Our job is to deliver a smooth practice programme, apply our learning from recent races and maximise the potential of the car, whatever that proves to be.
"We are now starting the heart of the season, with seven races ahead in the next ten weekends.
"We will race on a broad range of circuits before the summer break, with races coming thick and fast.
"This will test the team to its limits - and any weaknesses will be harshly punished in the points. We are clear-sighted about the challenge ahead of us and determined to prevail."