Mercedes trackside engineering director Andrew Shovlin has explained why the team ran Lewis Hamilton with a "less powerful" engine in Qatar despite having his Brazilian powerhouse in Losail.
Hamilton stormed from the back of the grid to fifth in the Brazilian Grand Prix sprint before recovering from 10th to take a dominant victory in the race itself.
In Qatar, the seven-time champion was again dominant but this time without the engine that had been fitted new just one week previously.
“Well, it wasn’t the engine, the fresh one, that we took in Brazil," said Shovlin in Mercedes' debrief video.
"This was an older engine and because it is older, it's got a bit less power."
As for the question of why the more powerful engine was not used in Qatar, Shovlin pointed to the calendar with both remaining venues, the Jeddah Street Circuit and Yas Marina, favouring cars with strong straight-line performance.
"Of the remaining circuits, Qatar had got the shortest amount of straight line, the shortest amount of full-throttle running and it's got an awful lot of cornering," Shovlin explained.
"So, the power advantage you get from that engine in Qatar is much smaller than if you run it at the two remaining circuits.
"All we are doing is really trying to balance the mileage across the pool but make sure that when we use the less powerful engine, there is less of a penalty for it and that also means when we get to the final two tracks, we are going to have the most power that we possibly can.”