Stage 18a, which was held in the morning, had a summit finish on the Col d'Aubisque. Roche attacked on the final ascent and won the stage, taking one-and-a-half minutes out of Hinault's lead. According to LeMond, Hinault was suffering so badly this time that he had to push his teammate in order to conserve the race lead. Stage 18b in the afternoon was won by Roche's La Redoute teammate Régis Simon, who won a two-man sprint to the line against Álvaro Pino (Zor-Gemeaz Cusin). After the two split stages, Hinault's lead over LeMond stood at 2:13 minutes, with Roche in third, 3:30 minutes behind.