If something has happened five times previously and always with a negative result, it stands to reason there's little justification to expect a different result. Ferrari set the Friday practice pace at Spa, the sixth time that has happened in 13 races in 2019 - so why should that confer it the status of favourite?
It's a valid question, but Ferrari's astonishing failure to win a single race this year has not always been down to a loss of relative pace from Friday to Sunday. The performance profile of its cars on Friday is exactly in keeping with what we'd expect from a car that should be the quickest here given its strength on the straights. But there are still reasons not to be "blinded" by the performance, as Sebastian Vettel put it.
Comparing the fastest Ferrari times in each sector to Mercedes' quickest underlines just how dramatic the advantage on the straights was
Ferrari certainly played to accentuate its strength in practice. It had a choice of three different front-wing downforce levels and opted for the lowest level on both Charles Leclerc and Vettel's cars.