Indeed.
I think in one lap Perez took out 3.5s, from Alonso. I don't think Ferrari expected that sort of dramatic drop-off. But this is the conundrum, as shown today, Vettel and Ferrari do not yet understand their tyres and lack the ability to reliably predict their performance/longevity.
And what about MSc. By far the unluckiest driver currently in F1. He certainly used up all his luck in his first career.
impressive considering both only did 1 stop.