"For too long, we've allowed ourselves to be bullied," he said.
"As a unit, we're a good enough team to compete with all the teams, but it's up to the guys to believe that.
"It's a simple philosophy. They played well against Horowhenua Kapiti because there's that mental attitude that there's the top three and the bottom three.
"It's that I find annoying - because we're better than getting bowled out for 50 by Taranaki and 90 by Manawatu."
The new face for today's game is the elevation of 16-year-old Collegiate prospect Connor O'Leary, who showed good wicket-taking form with the Central Districts Under 17s during their national tournament in Christchurch this month.
O'Leary had joined the group with Sam Beard's groin injury still not right, and now finds himself in a prominent bowling role after Ryan Slight pulled his hamstring during a sprint session at training on Wednesday.
"We've got enough bowling cover there so the decision was to rest the two of them," said Gillespie.
Expecting the wicket to suit pace, spinner Bryant Galpin has also been left out with opening batsman John McIlraith able to perform the slow bowling if necessary, while Chris Sharrock can have a trundle if the main bowlers Ross Kinnerley and Nick Harding have troubles.
"We've got a seam attack that covers all the options. We've got to pick an attack that we think we can win with," said Gillespie.
"[O'Leary] had a very successful tournament and I think he's got a lot of potential and ability."
But bowlers need targets to work with and after the batting failures against Manawatu, Todd Inness has been dropped, while Gillespie is extolling someone from his young top order of Morgan Inness, Mathew Boswell, Greg Smith and Dominic Lock to dig in and provide the anchor innings the team desperately needs.
Lock is a classic case of the mental block - as his two cheap dismissals against Manawatu was followed by a match-winning 115 for St Johns Tech in the Coastal Challenge Cup semifinal last Saturday.
"I had a bit of a chat to Dom last night, he knows himself it's an attitude thing - taking that relaxed approach from club cricket to rep cricket," said Gillespie. "Nick Harding has to understand that if he bats, he thinks like a [controlled] batsman and when he bowls, he thinks like a [aggressive] bowler. We've got guys that can get to 20-30, but it's taking that to 70-100 that they've got to learn to do.
"It's only a small percentage who have actually stood up to be counted. A couple have been earmarked and they need to pull their socks up and get some runs."
Wanganui's cause has been helped by the withdrawal of Wairarapa's inspirational skipper Henry Cameron, who will be in Australia, while Central Districts age group representative Liam Burling is also out.
Cameron in great form last weekend, smashing 125 from 66 balls in a club Twenty20 match. It will fall to openers Mason Hughes and Alex Treseder and the other top order batsmen in George Deans and Robbie Speers, to fill those big shoes. Dean van Deventer, Daniel Ingham, Stefan Hook-Sporry, Kelsey Fahey and Brock Price will be the bowling attack, while Gordon Reisima takes over the captaincy.
