By Gabriel Tan
The Sharks booked their place in the knockout round two weeks ago but face off against Home United on Tuesday looking to secure top spot in Group G and gain home advantage in their one-legged Round of 16 tie.
Speaking at Monday's pre-match press conference, Withaya stressed the importance of finishing top of the group, and also revealed he has set his players the target of making it all the way to the final.
"A draw will be enough for us to finish top too, but we want to win," Withaya said. "It's very important to get home advantage.
"We aim to make it all the way to the final."
His sentiments were echoed by captain Therdsak Chaiman, who remains confident despite expecting a tough test against the Protectors.
"We have confidence and we want to finish first in the group," the Thailand international said.
"We are determined to play at home in the next stage.
"It won't be easy against Home United but we will try our best and give 100%."
Home coach Lee Lim-saeng also admitted home advantage will be crucial in the knockout round, although he expects a real test against the Sharks at the Bishan Stadium.
"I really hope we can play our knockout round tie in Singapore," Lee said. "And we will try our best to achieve just that.
"It won't be easy as Chonburi are a very good side."
The last time both sides met, the Thai giants claimed a 1-0 win at the Chonburi Municipality Stadium thanks to former Home star Kengne Ludovick, who scored a 69th-minute winner.
Lee admits Chonburi had posed a tough test back then, and is prepared to risk suspension for a number of players by naming a full-strength lineup.
"We cannot afford to think about the next round yet; winning on Tuesday should be our only focus for now," the former Korea Republic international added.
"When we played them away, we wanted to play our style of football but it was very difficult as Chonburi were better than us.
"I'm still undecided about our tactics for tomorrow's [Tuesday's] game but we will try our best."