Although Sainz’s Toro Rosso team are fourth in the constructors’ championship, the Spaniard thinks that it is Williams that holds a slight edge in both qualifying and the race.

However, he feels that one of the key factors that is allowing Williams to shine – especially on Saturday – is the way that Mercedes’ qualifying engine modes can give it a big boost for the Q3 runs.

Asked about the gap between Williams and Toro Rosso, Sainz said: “It is not a lot. I think in qualifying they have those three tenths, but in the race we cut it back because the engine mode of Mercedes in qualifying is something that still no one understands.

“You can see from Lewis [Hamilton] the way they suddenly turn it up in Q3 – they [Williams] obviously turn it up also. But I think in the race we can still play a bit with them even if they are a tiny bit faster.”

Although feeling that Williams is leading the fight behind Mercedes, Ferrari and Red Bull right now, Sainz thinks the midfield battle will fluctuate a lot over the campaign.

“It is going to change race by race, I am 100 percent sure,” he said. “Especially because it looks like Force India here brings an upgrade.

“We will probably bring one for Barcelona and then we will have the Renault upgrade and upgrades through the season. So it will change and vary for the moment.

“I feel like Williams have the strongest car of the midfield definitely in both qualifying and the race. And then there is the rest.

“I am not brave enough to pick up one out of the three [others Haas, Force India, Renault], because it is extremely tight and then it depends on two tenths on a qualifying lap. It is exciting.

"I am enjoying it a lot this year because for me the fight is to be the best non-Mercedes, Ferrari or Red Bull cars.

“I am fighting against a very talented midfield this year. It is a different F1 to the top six, but it is an exciting one. I am finding a lot of motivation to push and happy to be leading it now.”