Fernando Alonso has revealed a "misunderstanding" with his Alpine team during Q1 cost him the chance to reach the second stage of Spanish Grand Prix qualifying.
The two-time F1 champion will start 17th - his lowest grid slot for his home race since his debut season with Minardi in 2001 - after getting caught up in traffic ahead of his final run of the session.
That left him unable to find a gap and becoming tied up behind McLaren's Lando Norris who had seemingly blocked Alonso who was arriving at the final chicane at a greater speed.
But after the FIA stewards noted the incident it was soon evident the Spaniard was rushing on his out-lap.
Explaining why he failed to complete a meaningful final attempt before being eliminated, Alonso said: "It was a misunderstanding in quali.
"I started a lap behind Lando thinking I had one or two seconds margin with the red light, but then I had like 20 seconds margin.
"If I knew that in advance then I would have created more gap to Lando and done my own lap but I heard on the radio it was very tight, I need to go now.
"So I went immediately when they told me and it was not necessarily the end so that was a misunderstanding with a high price.
"Barcelona, if you start at the back, everything becomes more difficult."
Alonso hoping for "mega fantastic safety car"
Barcelona is one of the more difficult circuits on which to overtake, with only eight of the races at the venue being won by someone other than the polesitter.
On whether a clever strategy could promote him through the order, Alonso conceded: "There is not much you can do.
"It is Barcelona, not much overtaking, a lot of tyre degradation when you run behind cars so we will see.
"In the last couple of races, people starting at the back have got very lucky and scored points. I am one of those tomorrow so if I have one of those mega, fantastic safety cars, I can get lucky and get a couple of points.
"But I doubt it. I think it is going to be a difficult race."
Additional reporting by Sam Hall