McLaren director of engineering Matt Morris maintains the outfit is "definitely ahead" compared to where it was in 2015, despite a disrupted final day of testing in Spain.
Fernando Alonso was able to complete only three installation laps, at which point McLaren detected a coolant leak, which required the majority of the afternoon, and he was not able to return to the circuit.
However, McLaren is optimistic that it has made good progress across the opening week of testing at the Circuit de Barcelona-Catalunya.
"Unfortunately, the coolant leak we experienced on the car today was in a tricky position, which meant it took longer than usual to locate and fix," said Morris.
"It’s always frustrating when a small issue hampers your running for much of a day, but thankfully it’s relatively minor and we can now look to preparing the car for the second test on Tuesday. Testing is testing, and it gives us the opportunity to identify and work on reliability issues before we start the season.
"Over the course of the first four days in Barcelona we’ve done a good amount of running and already learned a lot about our package, which should stand us in good stead for next week.
"We’re definitely ahead of where we were last year in terms of system checks and integration, so at the second test we’ll be able to focus more on race simulations and setup, as well as characterising our package’s performance."