I had the same feeling playing Red Fire as a child. Pacing around the house with my gameboy and my insides tied in a knot

Music added to the tension beautifully too
When the rival pulls out a Hyper Potion

shyt would break your moral
Worse thing was getting your Pokémons one shot and cycling through the surviving ones trying to Revive the rest of your team
Red Fire was even crazier since you had a shadow Elite Four after you beat them the first time. That was so fire. They didn't just take the L, they trained afterwards and came back with new Pokémons, new moves and much higher levels.