Bayer beat the Spanish side 1-0 on Wednesday thanks to a goal from Hakan Calhanoglu in the second half of their last 16, first-leg clash at home in Germany.
Atletico had midfielder Tiago was sent off for the final quarter of an hour for a second booking.
Son says his Leverkusen side will need to play very well in Madrid to reach the quarter-finals.
"It was a very intense game and we'll need to play like this again in Madrid to get a chance to go through," said Son.
"We know they are very strong at home, but we want to enjoy the win after a superb performance from the team."
Leverkusen coach Roger Schmidt says there is everything to still play for in Madrid.
"The door is still open for Atletico, but we have shown we are also good for a goal or two, “he said.
"We have to try and score in Madrid, which will really give us a chance."