"It is a big game and we are dying to put the whole threat of relegation behind us - and hopefully then we can enjoy the last two games," he says.
"We know what we are going to encounter on Saturday and there are no ifs or buts for them, they have to go all out.
"We will have to match them for that and if we don't, we will get turned over, it's as simple as that.
"There's a bit of nerves at this stage of the season with players being in positions they have never been in before, but you have to try and foget that."
Frank insists that the experience of this season, though largely unwelcome, will make the players mentally tougher and explains:
"You have to understand this is part of the game and hopefully we will benefit from it; as an individual it makes you stronger in the long run.
"We have to be confident we can get out of it and then look to next season.
"But it does hurt the pride; since I have been involved it hasn't been on the agenda at all.
"We're not happy with this season, obviously, because we feel we are better than what we have done.
"Everyone has got to look at themselves and make sure we don't commit the same mistakes next season.
"We've had ups and downs all season, you can't just pick one game.
"At one stage we were sixth in the league and everyone was talking about Europe but it didn't happen.
"The Tottenham match was the turning point and after that it has spiralled in the league.
"We have to make sure we don't go down, which there is a slight possibility of - if we lose at the weekend we'll be deeper in it than we are now by a long way.
"You have to try and keep your confidence but it is not easy; certain players are encountering stick which they've not had to deal with before.
"But you have to be strong and put up with it because that is part of the modern footballer's life."
Frank feels the voracity of praise and criticism is a double edged coin and explains:
"As much as people like to give you credit for when you are doing well, and perhaps go over the top, equally they go over the top sometimes with giving you stick.
"But you have to keep an even keel and not get too despondent when it is not going so well - you learn that as you go along.
"There is not one player who doesn't have a bad time in his career and you have to get over that."
Frank admits that seeing Rio at the weekend emphasized the change in fortunes West Ham have had this season, and says:
"We have had a few problems this year with injuries and Rio leaving - that was a big milestone in the season.
"But we have to move on from that and be strong; we can't look back at the past.
"Rio is a fantastic player but he left to go on to better things for him, and that's as far as that goes.
"Leeds have spent near on £50m or £60m and good luck to them.
"We have our own battles to fight, and hope we keep making forward strides."
Frank is sure the days of West Ham being a selling club are drawing to a close and says:
"The players don't want that and the fans don't want that - Rio left but I don't think there are many teams anywhere who can turn down that sort of money, it's not just West Ham.
"We haven't spent great deals of money; that is the way it has been at West Ham over the years, but we have to get on with it - we've definitely under achieved because we have got quality players in the squad.
"I saw Rio after the game and congratulated him as you do; it's funny to see him scoring goals, though he didn't score many for us, did he?
"But he has a soft spot for West Ham and he more than anyone wants to see us doing well though his priority is Leeds."
And did he, as reported, give Rio a dirty look after he notched?
"I read that somewhere but I didn't do that at all - I was just disappointed," he insists.
"It is up to him to do what he wants when he scores, but the fact that he didn't celebrate shows he has got some respect for the fans, and they showed him a lot of respect."
And the rumours of him following Rio to Yorkshire?
"I just read it like everyone else, to be honest."