George Russell has revealed that a software glitch buried deep inside Mercedes' new power unit forced him to change his driving style for races on end — and that the team only found the root cause after he failed to finish the Belgian Grand Prix at Spa on 19 July.

The new generation of Formula 1 power units — the hybrid engine systems that combine a turbocharged combustion engine with electric energy recovery — are, in Russell's words, "exceptionally complex." The problem, he explained, was "deeply embedded in the calibration and the code" and was "almost impossible to see unless you knew exactly what to look for." It affected how the car managed electrical energy around a lap, a process known as energy management: deciding when to deploy stored battery power and when to harvest it back through braking. Get that wrong and the car either runs out of boost on the straights or cannot charge quickly enough through the corners.

Russell told Yahoo Sports the circuits at Spa and Silverstone "probably exposed the issue" more than any others, because both tracks demand long, sustained periods of energy deployment that left the flaw visible in the timing data. He admitted he had spent a significant amount of time trying to adapt his driving to accommodate the power unit, rather than simply trying to drive fast. "I definitely feel this is the most resilient I've ever been," Russell said, in an interview published on 23 July Yahoo Sports.

The breakthrough came after Spa. Russell did not finish the Belgian Grand Prix — won by his Mercedes team-mate Kimi Antonelli, who started from pole — and the team recognised afterwards that the problem lay not in Russell's driving but in the power unit's software. According to the Associated Press, Antonelli's victory delivered a significant boost to his own title campaign, coming as it did with Russell out of the race WKRG/AP.

For Russell, Spa was a low point in a season that had promised much. He took pole position at the season-opening Australian Grand Prix in Melbourne, leading a Mercedes one-two in qualifying while Max Verstappen crashed, and went on to start first at Barcelona and Austria. He won the race in Austria and also took the China Sprint victory in March — his second career Sprint win. His pace in Melbourne was underlined by topping the sole practice session in Shanghai with a lap of 1:32.741 FIA.

Team principal Toto Wolff called Russell Formula 1's most resilient driver earlier in the season and said it was far too early to write him out of the title race ESPN. The current championship leader is Lando Norris, described in the same BBC report as "the world champion." Lewis Hamilton, meanwhile, stated that "Mercedes are still the team to beat" heading into this weekend's Hungarian Grand Prix BBC Sport.

What makes Russell's situation stand out is the nature of the problem itself. A driver can adapt to a tricky car. A driver cannot fix code he cannot see. Russell was effectively trying to solve a software fault from the cockpit, changing his inputs lap after lap while the real issue sat hidden in the calibration — invisible unless you knew precisely where to look. Now that Mercedes have identified it, the question is whether Russell can convert his qualifying pace and Sprint-winning speed into consistent Sunday results. Hungary will offer an early answer.