The Finnish driver was leading the rally by 5.3sec from six-time winner Sébastien Ogier, but disaster struck when his Hyundai i20 N careened off the road and collided with a utility pole 10.01km into the opening Ibarrilla test. The car then burst into flames, prompting the stage to be red-flagged.
This is not the first time that Lappi has endured a fiery end in Mexico. In 2020, the 32-year-old was forced to retire when the Ford Fiesta he was driving at the time burst into flames.
With Lappi out of contention, Ogier inherited the top spot and now leads the rally by 27.3sec from his Toyota Gazoo Racing team-mate Elfyn Evans.