Italian GP: Toro Rosso makes tactical F1 engine changes

Verstappen will take a seventh power unit of the season which will result in a 10-place grid penalty while Sainz has a 20-place drop because the change will be his second of the weekend.

It follows sister team Red Bull's decision to do a double engine change on both Daniel Ricciardo's and Daniil Kvyat's cars this weekend.

Meanwhile, McLaren-Honda followed up its double change in Spa with a single change at Monza.

Verstappen said his change was tactical, as Renault's lack of power will be amplified at Monza, but he said the timing was not as well planned as it could have been.

"It's quite painful to have to do the change," Verstappen told AUTOSPORT.

"Red Bull and Carlos - they do two engines, I think it's a bit better planned.

"I did one in Spa and one again [here] so that's not ideal, but we just take it.

"We were waiting for the first two practices. If I was in the top 10, I don't think we would have done it - but we are quite far off.

"We know this weekend is going to be tough for us. It's not good but it's better here than somewhere else.

"It's a good thing because we'll have more engines for Singapore, where we can normally score."

Sainz was already destined to start towards the back having had an engine change this weekend after an electrical problem at Spa, so fitting a second engine will have minimal impact on his grid slot.

"We all know why we took the penalty, it's because it is not the best track for the STR and our power unit," said Sainz.

"The car feels good. I had a couple of long runs and a couple of short runs but the stopwatch doesn't lie, we're not quick enough.

"I stay positive and I'm going to have some good fun starting with two Red Bulls and two McLarens. The opening laps should be good."