Steve Bruce has described the suggestion Newcastle have been lucky this season as “an insult” but acknowledged he dare not risk his team’s Premier League status by experimenting with a less pragmatic approach.

With a debate about his mid-table side’s style – or lack of it – raging on Tyneside, Bruce is probably relieved to be travelling to Oxford for Tuesday night’s FA Cup fourth-round replay. Victory would offer Newcastle a trip to West Brom in the fifth round for the first time since 2006 but avoiding an embarrassment against League One opposition at the Kassam Stadium will surely necessitate the visitors summoning up some elusive creativity.

Some critics believe the safety-first 3-4-3 system Bruce inherited from Rafael Benítez is at the root of the problem but he is not tempted to deviate from it any time soon. “I don’t think we’re ready to change,” said Newcastle’s manager, who would, ideally, overhaul his squad in the summer.

“I could change tomorrow and play the way Norwich do quite easily but I think that, if we changed to four at the back, we’d be in trouble. The players we’ve got are comfortable in the system we have. It’s the most effective way of keeping this team in the Premier League. It doesn’t really look like ‘my’ team yet but, as soon as I try to open us up a bit, we start to struggle.”

Bruce bridles at suggestions he has enjoyed a fortunate St James’ Park tenure. “In the past couple of weeks maybe,” he agreed. “But I can’t see that our accumulation of points over the past seven months of the Premier League is luck. I think that’s an insult to the players. I really, really do. They might not be the best technically but they go out and give as much as they can. That’s all you can ask.”

If Newcastle were a little lucky to beat Chelsea before drawing with Everton, Oxford and then Norwich, despite playing poorly in all four instances, Bruce believes fatigue proved a mitigating factor.

He is annoyed that Tuesday’s game cuts into the supposed winter break but would not scrap replays. “I think we’ve got to restructure the whole season,” he said. “Why not start it a week earlier, or finish a week later? I understand that, for a club like Oxford, this replay probably means being able to sign a player but I also understand it’s ludicrous to expect top players to keep going every Tuesday and Saturday. In my humble opinion we should do away with international friendlies.”

He must cope without two loanees in Danny Rose and Valentino Lazaro at Oxford as neither signed in time for involvement but he hopes to field Matty and Sean Longstaff, despite both brothers having currently failed to agree new contracts.

Matty Longstaff is now in the final six months of his deal and has been watched by Milan and Internazionale. “It’s a concern,” said Bruce. “It really is. I hope both Longstaffs get tied up but the players have the power today. I hope there’s a bit of common sense shown.”