Christie Elliott insists Partick must start showing the "uglier" side to their game if they are to start winning matches again.
Thistle head into Sunday's William Hill Scottish Cup fourth-round tie against Aberdeen at Firhill on the back of four straight defeats in the Scottish Premiership.
Elliott says the top-flight newcomers have tried to impress with their brand of attractive football.
But he believes now is the time to start showing their ruthless streak in order to pick up some much-needed results.
The forward said: "Our results haven't been the best but we just have to stick together.
"Hopefully we can bounce back with a win and get our confidence back to the way it was when we started the league.
"The manager has been disappointed. We've been playing pretty football but that doesn't always win games.
"He kind of wants us to bring the uglier side to the football and just change the approach and be a bit more ruthless."
Partick started the season well but Christie admits they may have had the element of surprise on their side in those early encounters.
He added: "Not a lot of teams knew exactly how we played and that worked in our first few games.
"But the last few results haven't been the best and now it's time to change it."
Partick have already endured a couple of heavy defeats to Aberdeen this season.
They slumped to a 3-0 home loss in September before the Dons claimed an emphatic 4-0 victory at Pittodrie earlier this month.
And Elliott admits the Glasgow side are desperate to make amends for those results.
He said: "They have been a brilliant team and they have brilliant players all over the pitch.
"We've just got to stick together and we need to start taking our chances.
"They've hammered us in the last couple of games but we want to prove that we can beat them."
But he was adamant Partick should not dwell too much on those previous meetings with Aberdeen.
He added: "Those games are in the past. We just have to look to this game now."
Partick boss Alan Archibald has selection issues. Gary Fraser, Aaron Muirhead and Stuart Bannigan are all suspended for the fourth-round tie while Sean Welsh, Stephen O'Donnell and Jordan McMillan are injury doubts.
Defender Andrew Considine believes Aberdeen have the maturity and determination to bring home the silverware he feels the supporters deserve.
Considine's late headed goal helped 10-man Aberdeen to victory at Motherwell last month, setting up a League Cup semi-final against St Johnstone.
Derek McInnes' side now begin their Scottish Cup campaign against a Partick Thistle side who have shipped seven goals against the Dons this season.
Considine said: ''I felt strongly this year a lot of the younger members of the squad have grown up this year.
''I think that's with playing every week and having confidence instilled in them from the manager and Tony (Docherty) and I feel it's given us a real determination and confidence and it's shown in the league and we just need to keep doing that in the cup.
''I think it epitomised what we're all about when we played Motherwell with 10 men and to keep going to the very end.''
The 26-year-old spelled out what it means to bring some cup success to a club who have not won a trophy since the 1995-96 season.
''It's massively important for a club like Aberdeen,'' the centre-back said.
''We want to get as high as possible in the league but I feel we owe ourselves, the club and the supporters a good run in the cup. It would be great to win a cup this year.
''The confidence is high within the squad. I feel we have the players to do it this year but full respect to Partick Thistle on Sunday.
''It's going to be a really tough game but if we go into the game in the right frame of mind we can hopefully come up the road with a win.''
Considine brushed off the importance of their recent 3-0 and 4-0 Scottish Premiership victories over the Jags.
''When it comes to cup games it's completely different,'' he said. ''Whichever team turns up on the day and wants to win it most will win.
''Both games have been very open. They play some real good football and have some good players going forward. So it will be good game of football.''
Aberdeen have an injury doubt over winger Jonny Hayes but midfielder Chris Clark is back in contention after a long-term knee injury and former Scotland midfielder Barry Robson returns to the squad following suspension.