Guangzhou were beaten 1-0 when they hosted Seongnam on March 17, but Contra acknowledged that his side will be pushed to their limits when they travel to the Tancheon Sports Complex.
"We know it won't be easy to win at the home of a team like Seongnam, but that is what we will try our best to do," Contra told the South China Morning Post.
"Seongnam are strong defensively and counter-attack very well but I trust the players I select will be able to handle the situation. They know full well how important this game is."
To make matters worse for Guangzhou, who are third on the Group F standings with three points, they will be without the services of Korean defender Jang Hyun-soo who is suspended for one game after picking up his second booking in the 1-0 loss to Seongnam.
"Jang's absence is obviously a minus point for us but the other players will do their best until he returns," Contra said.