In Austin the Mercedes driver had to check his pace to save fuel, and in Mexico he had to do the same to control spiralling brake temperatures, having spent many laps trying to find a way past Carlos Sainz.
On both occasions when he was able to push harder once again his tyres wouldn’t respond.
In Mexico he finished sixth, having lost out to Lando Norris in the closing laps, while just managing to keep Daniel Ricciardo at bay.
"It was just a race dictated by tyres once again,” he said when asked by Autosport about his afternoon. “The car felt really strong, I was right behind Carlos, just couldn't quite make the overtake.
“But we had to back off because my brakes were overheating, as they were for many drivers. As soon as I backed off, I totally lost all the temperature in my tyres, and could never recover it.
“It was like driving on ice for the last 15 laps, and a pretty miserable feeling and very lucky to finish P6.”
Russell said the positive was he understood why he had lost performance.
“It's never fun when you're the defending driver on the backfoot,” he noted. “Again just really struggled throughout that race with the tyres, and it was pretty clear as soon as I backed off, I lost all the grip, and I couldn't recover it.
Source: Autosport