Home beat Albirex Niigata in last year's final to claim Singapore's premier cup competition but were handed no favours on Sunday after they were pitted against DPMM in the opening round.
And having seen his side toil to a 1-0 win over the Bruneian outfit in the Great Eastern-YEO's S.League earlier this season, Lee is aware the Protectors face a tough test in their bid to book a spot in the quarterfinals.
"DPMM are a good side," Lee told ESPNSTAR.com. "Even though we beat them 1-0 earlier this season, we cannot afford to be overconfident.
"It's up to the players. Everybody wants to be champions but hopefully we can do it again this year.
"We'll just do what we can on the pitch and see how it turns out."
With Home also challenging for glory in the league and the AFC Cup, the fixture pileup is something that could potentially come as a worry to the Protectors, although the South Korean coach is focusing on a game at a time.
"The fixture pileup is unavoidable if we want to be successful," he added.
"What we can do is prepare for the game so we can bet DPMM and then worry about the quarterfinals."
Should Home progress from their opening round tie, another difficult test awaits them as they are set to meet either Balestier Khalsa or SAFFC.