New Zealand held off an Argentina side featuring incoming Leicester Tigers lock in a thrilling opening to the Rugby Championship in Buenos Aires.
Lavanini played more than an hour from the start in the Pumas second row, just two weeks after featuring in the Super Rugby final for the Jaguares.
First-half tries for Ngani Laumape and Brodie Retallick saw New Zealand lead 20 points to nine at half time, with Argentina scoring penalties through full-back Emiliano Boffelli and fly-half Nicolas Sanchez.
And it was Boffelli who went over at the start of the second half as the Pumas fought back to within four points, though that would be the last of the scoring as the All Blacks held firm against an abrasive Argentina attack.
Lavanini and Argentina next face an Australia squad featuring former Tigers back Matt Toomua in Brisbane this Saturday, July 27.