Temperatures are expected to hover between 27 and 37 degrees, and with humidity set to be high, conditions will be tough for the Osaka-based outfit.
Hasegawa is wary of the fact that his team will have to avoid being beaten for a third time if they want to have any chance of progressing to the next round.
To make matters worse, Gamba will be without defender Patric as the Brazilian is suspended for one game after picking up his second yellow card during Gamba's 1-1 draw against Buriram on March 18.
"The hot weather is our problem, but we spent a day in Bangkok," Hasegawa told the official AFC website. "This makes us adjust ourselves.
"We will do our best even though the weather is very hot. Apart from this, we will make a decision which one is going to replace Patric.
"We still have hope for this game. We believe that we have the potential to get three points if we do our best."