For Sheffield Wednesday, this season is not a question of how they win, just how often

On the face of it, an unconvincing 2-1 FA Cup win over League Two Mansfield Town had nothing to do with winning promotion, but much of what happened on a largely forgettable afternoon at Hillsborough fed into the qualities required.

For 78 minutes, a much-changed and unsurprisingly disjointed Owls were very poor. But they have a deep bench and the determination and ability to grind out results when below their best.

Darren Moore's side are unbeaten in eight home matches but even on their travels there is a sense of a team that cannot be discounted until the final whistle.

“The manager told me when I signed this place is a fortress," explained Michael Smith, whose two goals made the difference. "They are very proud of their home record and he wants to keep that going. As long as we can keep the away form ticking over, this will always be a hard place for teams to come."

Twice in five minutes Marvin Johnson perfectly weighted low crosses for substitute Smith to stretch out a leg for the kind of goal Owls centre-forwards have not scored enough of this season.

The ex-Rotherham United man might have had a hat-trick when Johnson showed an astonishing burst of pace for the 87th minute of a match he started, only for goalkeeper Christy Pym to cut the cross out. Callum Paterson’s shot from the loose ball was saved.

To have won 3-1 would have been taking the micky given how poor the hosts were – and how well the Stags played – and even after that George Lapsile and George Maris missed good chances to secure a replay.

But from the minute Smith first netted it was clear not just that the Owls would be in Monday's third-round draw but that Mansfield would not. Good sides can build that sense of inevitability and trade on it.

In years to come if this game is even mentioned, there will be no asterix saying "but Wednesday were very lucky to win".

Just as for long periods they did not look like a team hoping to play in next season's Championship, so Mansfield – backed by a magnificent following of around 4,000 – looked nothing like a side beaten 3-0 at Harrogate Town seven days earlier.

In the first 90 seconds Lapsile had a shot blocked, Cameron Dawson touched a Kellan Gordon cross onto the post and Lucas Akins headed the rebound onto the roof of the net.

So it was no surprise Mansfield took a 34th-minute lead, right-back Gordon’s left foot dinking a lovely curled ball Lapsile ran between the frozen centre-backs to convert.

Dawson ended the half denying former Sheffield United player Stephen Quinn, who patiently waited in a three-man queue to shoot.

For 15 minutes after the restart, the Stags kept up the pressure with only a glancing Gregory header to worry them. Then the game fell into a slumber, Mansfield wary of conceding, Wednesday not only looking unable to break them down, but showing little desperation.

"The cohesion of the team wasn't there," admitted Moore. He changed formation to 3-4-1-2, pushing Johnson further up, and introduced Barry Bannan and Smith.

"I didn't want to put them on," he revealed, raising Smith’s eyebrows when that was relayed to him.

“Any game you’re not involved in is frustrating," said the striker, brought on after 63 minutes. "You’re itching to make an impact."

Wednesday have a bucketful of goal of the season contenders but Smith trades on tap-ins. The skill behind Johnson's deliveries – not to mention the passes to release him – and movement of Smith are not to be underestimated.

“I didn’t touch the ball for ten minutes after coming on," said Smith."There's been a few times this season when Marv or Palms (Liam Palmer) have got to the byline and I've not read the ball they've put in so it's about building relationships on the pitch.

"I'm never going to score a 30-yarder like Baz (Bannan) or Fizz (Dele-Bashiru) but I'll take them off my backside, they count the same."

Likewise with wins. This season it is not about how, just how many.

Sheffield Wednesday: Dawson; Hunt (Iorfa 63), Palmer, Ihiekwe (McGuinness 89), Johnson; Dele-Bashiru, Vaulks; Wilks (Smith 63), Paterson, Mighten; Gregory (Bannan 72). Unused substitutes: Stockdale, Brown, James, Shipston, Glover.

Mansfield Town: Pym; Gordon (Wallace 90), Harbottle (Perch 79), Hawkins, Hewitt; Maris; Akins, Boateng, Lapsile, Quinn; Swan (Oates 79). Unused substitutes: Flinders, Hartigan, Bowery, Law, Gale, O'Toole.

Referee: O Yates (Staffordshire).