Spaniard Martin won last week's Indonesia MotoGP to take a 21-point lead over Italy's defending champion Bagnaia, who finished third at the Mandalika track on Lombok island.
The result leaves Pramac's Martin and Ducati's Bagnaia locked in a virtual two-way battle for the title with five races remaining, starting this weekend at Motegi.
Martin won last year's Japan MotoGP in a race cut short by rain, and he said he will "start from zero" this year with more bad weather potentially on its way.
"Last season for sure was good, but it was a different situation, I was coming from behind trying to attack," said Martin, who is looking to win his first MotoGP championship.
"I won the sprint and the Sunday race but I think this time will be different, it will be tough.
"I see that the weather forecast is quite unpredictable so it will be also difficult and really challenging."
Martin crashed out of the Indonesia sprint, won by Bagnaia, but triumphed a day later in the Grand Prix when the Italian finished third behind Spain's Pedro Acosta.
The results enabled the top two to increase their gap on the chasing pack, led by third-place Enea Bastianini who is 54 points behind Bagnaia.
Spain's six-time world champion Marc Marquez is three points further adrift in fourth.
Martin refused to rule out Bastianini and Marquez from the title picture but admitted that their chances are fading.
"If somebody can do it, it's them, but I feel it's quite difficult at the moment," said Martin.
"I feel it's more about Pecco (Bagnaia) and me. For me it's a pleasure to be able to fight with a champion like Pecco, like Marc, an amazing rider like Enea.
"Let's see what happens."
Last year, the roles were reversed with Bagnaia leading the championship and Martin trying to close the gap in second.
Bagnaia said it was "nice to be fighting again" with Martin.
"It looks exactly the same but on the opposite side," said the Ducati rider.
"I think with Jorge it's nice to have a battle again. We always have a fair battle, a fair fight and a fair respect between us."
