When Verstappen was blocked on the inside line by Leclerc, he could only swing to the outside, deciding whether to brake late and fight into the corner or brake early to seize the crossover line.
Moreover, Verstappen felt that Leclerc's exit from the corner this lap was not that smooth, and his speed was somewhat affected by a bad exit.
Verstappen felt he could very likely overtake Leclerc on this lap, although he knew Hamilton was right behind him, getting closer and closer.
However, after battling Leclerc for so many laps, Verstappen was somewhat fired up and wasn't paying attention to Hamilton behind him. He was more focused on quickly overtaking Leclerc ahead of him. Once he overtook Leclerc, all the pressure from Hamilton would naturally transfer to Leclerc.