Second row Hayes, the younger brother of Ireland, Munster and Lions prop John, was at headquarters yesterday for a promotion photocall ahead of AIB finals day.
The 24-year-old, who was named in the AIB/Irish Times Team of the Season for the second year running on Monday, is adamant that the reigning champions cannot afford to be complacent.
"We'll give them their due respect. They're a quality side with some stand-out players and they will probably include one or two more additions from their Ulster-contracted ranks," said Hayes, whose side must plan without their own Celtic Cup-tied Munster contingent.
"They gave us a bit of a battering in the final quarter up in Belfast in December. We ended up on the end of a 19-18 defeat when we were 18-0 going into the closing stages.
"That was a shock to the system so we're well aware of what to expect from them. 'Quins have beaten some big teams this year - including the likes of Garryowen twice, Cork Con and Clontarf. They hav a big pack but we're quietly confident we can win successive finals."
Belfast Harlequins vice-captain Paul McKenzie also expects there to be little between the sides in the heat of Saturday's battle.
"Shannon are a class side and have a lot of strength in depth. I don't think there's too much between us - there could be a lot of cancelling each other out," said the current Ireland Under-21 winger.
"As a team, we're really focussed on doing Ulster proud on the day and following in the footsteps of the likes of Dungannon and Ballymena, who were both recent league winners."
Cancelling out is the operative word - Shannon were the top scorers in the league proper with 395 points scored while 'Quins were the meanest defenders, conceding an average of just 10 points per game.
If DC Gillespie's 'Quins side, who might be able to count upon Ulster stars Tommy Bowe and Kevin Maggs, can prosper they will become the second Ulster outfit since Dungannon (2001)to bring the top flight trophy back across the border. Ballymena, who 'Quins star fly-half Ian Humphreys previously played for, triumphed in 2003.