While Sergio Perez hailed his "great lap" that secured him a place in Q3 in Spain, Jenson Button was left frustrated.
McLaren arrived at Barcelona with several updates to their MP4-28 although didn't run a new front wing on Saturday as they ran out of time for it to go through scrutineering.
But even without the wing, Perez showed improved pace as he put in a great effort to get into Q3 where he eventually qualified in ninth place.
"It was a great lap," the Mexican driver told the BBC. "To be in Q3 is incredible for the team and for myself. It was something we were not really expecting.
"If we are able to maximise tomorrow, we can be satisfied.
"It has been disappointing to be in the position we are at moment, but the team is determined to keep fighting and this makes me hungry and makes me give my very best every session."
But while Perez showed signs of improvement, the same cannot be said for Button who finished a disappointing P14.
The Brit blamed tyre pressure issues for his lack of pace.
"The tyre pressures were massively high, so I don't know if something was wrong or if they were set wrong, but we're looking into it now," he told Autosport.
However, even if that hadn't been a problem, Button doesn't believe he would have been running at the front as he says McLaren's updates are just not enough.
"They're making a little bit of a difference but nowhere near enough to really challenge up the front and everyone has got new parts so it makes it very tricky for us to catch up.
"The good thing is the car with Sergio in it has shown we have made some progress, which is what we need and we need to build upon that."
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