Gary Johnson believes Bristol City fans have a crucial role to play this season.

City's manager has often referred to the Ashton Gate crowd as "our twelfth man" and the fans have again been awarded the number 12 squad number.

But Johnson insists it is more important than ever for home supporters to create an intimidating atmosphere when the Robins take on familiar foes Crystal Palace in their opening home game of the Championship campaign tomorrow.

Preston North End fans demonstrated just how persuasive a partisan crowd can be when baying for a penalty to be awarded in the dying seconds of last Saturday's game at Deepdale.

Northumberland referee Michael Oliver ignored a blatant foul on Bristol City's Marvin Elliott and instead awarded a penalty for handball, which provided Lilywhites skipper Callum Davidson with an opportunity to equalise from the spot and salvage a point his team scarcely deserved.

Johnson is urging Bristolians to create a similar wall of sound in the hope that more borderline decisions go City's way in the future.

He argued: "We all saw during the Preston game how a vociferous crowd can, on occasions, influence a result.

"I spoke to the referee earlier in the week and I still think he got it wrong. But when the crowd are crying out for something to be given, it is only human nature.

"If our supporters do the same thing when we play at Ashton Gate, then these decisions may even out over the course of the season."

Three of City's next four Championship fixtures are at home – Queens Park Rangers visit Ashton Gate on Tuesday and Middlesbrough are in town on August 29 – and Johnson is eyeing a chance to establish the Robins among the early pace-setters.

But City will have to improve upon last season's record at home when a total of 13 draws from 23 games effectively cost them a play-off place.

"It is absolutely vital we win our home games," confided Johnson. "Given that we play three of the next four at our place, we really do have a marvellous opportunity. But we need the fans to help us take advantage.

"Whenever I speak to opposition managers after games here, they always mention the crowd and the atmosphere.

"If we can get that noise around Ashton Gate again, especially early on in the season, it can help put us into a play-off position.

"Our crowd can be massive for us and help us stay where we want to stay in this league, which is at the top."

City will be boosted by the return of Paul Hartley, Jamie McAllister, David Clarkson and Lewin Nyatanga from international duty – and all four are expected to play.

But the one-match suspension meted out to Danny Haynes following his sending off in Tuesday's Carling Cup tie at Brentford means the manager must make a change in attack.

It seems likely that Clarkson will partner Nicky Maynard up front in the continued absence of a new striker.

Johnson still intends to bring in another forward before the transfer window closes at the end of the month and he is currently monitoring two unnamed targets. But no new arrivals are expected at Ashton Gate before the weekend.

Meanwhile, the transfer-listed goalkeeper Adriano Basso will again feature on the bench tomorrow. If Johnson's stated intention was to bring in a young keeper on loan from a Premier League club, he appears to have undergone a change of heart after seeing summer signing Dean Gerken perform outstandingly well in the games at Preston and Brentford.

Left wing-back Andre Blackman could be called into the squad after playing for 80 minutes in midweek, but tomorrow's game will probably come too soon for centre-back Jamie McCombe, who only returned to training yesterday after recovering from the effects of a knee injury.