The Eagles have won four in a row after starting the season 1-4 but have not beaten any side currently in the top eight.
"If we're serious about finishing in the top four we've got to beat the good teams in the competition, which Richmond and St Kilda are," Worsfold said on Wednesday.
"You have to be able to beat them."
"Every week is critical for us, for the eight, for the top four, for everything.
"Wins are what counts."
Only 17 teams in VFL/AFL history have started 1-4 and played finals, with Melbourne (1900), and North Melbourne (1975), the only two teams to win the premiership after losing four of their opening five matches.
West Coast has made the top four previously after a 1-4 start.
In 1996 the Eagles went on an 11-match winning streak following their horrendous start to finish fourth with 15 wins and seven losses.
Worsfold believes the Tigers presents a significant challenge for his side on a rare Monday night game at Patersons Stadium.
"I think Richmond are on a pretty good pathway to becoming a really top side, so they are going to present challenges all across the field for us.
"Adding (Troy) Chaplin in their back half has given them a good mix down there.
"Their forward line has got good talls as well as good pace and they are a very good midfield.
"We are really excited about the opportunity to test ourselves out against them."
Worsfold held no fears of his players switching off over the eight-day break following a 100-point drubbing of Greater Western Sydney.
"Consistently you are looking at how you prepare your players between games – short breaks, long breaks, both physically and mentally.
"We’re constantly monitoring how the players look and sound and we don’t have tricks, but we have strategies that we use."
Worsfold felt that Beau Waters and Adam Selwood still had not done enough to prove they have recovered from quad injuries that saw them miss last week.
"The first thing they've got to do is prove their availability.
"Neither have done enough today to say they're right to go, so we've really got to make that call tomorrow.
"We do have the opportunity to name them in the squad, but we won't do that if they haven't proven their fitness.
"If they need longer, they'll probably be in the squad."
Andrew Embley is a strong chance to return to the line-up after playing a second game in the WAFL to prove his fitness following a foot injury that has kept him out since round three.
"He just hadn’t done enough to come into our team last week in terms of match fitness, match preparation.
"So we felt another hit out was the best preparation for him to be able to come back in and to compete at the elite level that we know he can."
