Daniel Ricciardo has conceded he is "on the back foot" after a water leak limited his second practice running to just 12 laps ahead of the Bahrain Grand Prix.
The Australian was hoping to spend as much time on the track as possible this weekend after missing the final pre-season test at the Bahrain International Circuit having tested positive for Covid-19.
But this did not happen with the Australian able only to complete 12 laps during the more-representative nighttime running, ending with a time good enough only for P18.
"They saw a little bit of a water pressure loss so to get into it it's basically everything off and we obviously didn't have time to do it in the session," explained Ricciardo.
"It's not a fix we could do in the session.
"Obviously, I missed a lot of laps last week and would have loved to have got them today but it's alright.
"We're obviously a bit on the back foot but it's all good and there's plenty to look at tonight."
McLaren "lacking overall grip"
McLaren had left the first pre-season test in Barcelona with optimism of a strong challenge to start the 2022 campaign having finished top in two of the six sessions that week.
But with team-mate Lando Norris finishing only 11th fastest, the Woking-based team looks unlikely to fight with Red Bull and Ferrari at the top.
"We're obviously off the pace so need to figure that out but it's early days," said Ricciardo.
"I'd like to think that we can definitely get a bit better but we're don't have bags of sand at the moment so have got some pace to find."
Asked where the team is struggling compared to its rivals, Ricciardo added: "I think, honestly, we're just lacking overall grip.
"The car feels okay [but] when you're down a bit on grip you do struggle a bit more and lock a wheel here or there and make a few errors.
"But compared to the quickest cars at the moment I think we're just looking for some overall grip. There's never enough."