Daniel Ricciardo and Sebastian Vettel concede their respective teams, Red Bull and Ferrari, could be fighting for third at the Brazilian Grand Prix after Mercedes dominated Practice on Friday.

The two Silver Arrows led both sessions, with Lewis Hamilton just ahead of Valtteri Bottas, and though the gap wasn't too substantial between the top three teams, with less than four-tenths covering P1-P5 in the afternoon, it wasn't the single lap pace that particularly concerned their rivals.

“Mercedes are really quick on high fuel, we seem pretty close on low fuel but they are quick on high fuel,” the Australian commented afterwards. “I think they will have a bit more on low fuel for tomorrow, but relative to Ferrari we had a pretty good day though we need to find a bit more.”

Ricciardo's former teammate echoed his view, adding: “Yeah, Mercedes looked very strong, so I think they're a bit ahead, both of them. Then I think it's very close between us and Red Bull.

“We did a lot of laps today, it's more quiet on-track than off-track, so I enjoyed that," Vettel continued. "We'll see what we get tomorrow, I think we can fine-tune the balance and that should help us.

“As I said, it will be tough to beat Mercedes. They look quick in all conditions, all tyres. So we'll see.”

For Ricciardo, this weekend is more compromised as he will take a fourth grid penalty of the season and second in as many races after changing engine parts following his failure in Mexico.

Asked if the setbacks were becoming frustrating, the 28-year-old replied: “It is not perfect, it is not nice. I knew coming into the weekend it is going to be a likely scenario, so look we have the penalty now so all I can ask for is to finish the race.

“In the next two races, this engine has to get us to the checkered flag that is my wish now.”

Ricciardo doesn't see too much reason to change his approach going into the weekend, however, with possible opportunities in qualifying potentially negating some of the penalty's impact.

“It won’t change because it is only 10 places it still makes sense to try and fight for the pole, especially if it is wet,” he said.

“Maybe I will put it on pole tomorrow and then wake up Sunday in 11th, it is what it is. I don’t think we are far off. If we can find a little something, maybe the rain, maybe I will start 11th.”