Sheffield United: Are the two best teams in the transfer market going head-to-head at Bramall Lane tonight?

Both contain the odd aberration. On reflection, with the benefit of hindsight, United's decision to sell Dominic Calvert-Lewin for £1m reflects better on Goodison Park than it does Bramall Lane.

But that mistake arguably pales into insignificance when compared to the visitors' decision to accept United's £500,000 offer for Jack O'Connell. The sum, paid in two £250,000 installments, now seems like a pretty paltry amount for a left-sided centre-half likely to be worth over 30 times that amount.

They are, however, exceptions to the rule as deals for the likes of John Fleck, Oliver Norwood, Neal Maupay and Sergi Canos prove.

O'Connell, who value has been boosted by his decision to sign a long term contract with Chris Wilder's side, has been good for United; appearing in nearly 95 per cent of their matches since leaving Griffin Park and, after helping them win promotion from League One, emerging as a driving force behind their climb to third in the Championship. But, by putting pen to paper on that agreement, O'Connell has acknowledged that United have been good for him too; not least by simply giving him a chance to showcase and develop his footballing ability.

"I didn’t really play at Brentford, I was more of a squad player, on the bench every week," the 24-year-old said. "I was just itching to get back playing, because that’s all I have ever known, since I was a kid, just playing every week.

"I have got good memories from there, but when I came here it was a different ball game.

"We have got great bunch of lads, that comes from the gaffer, there is no big-time players in our dressing room.

"I don’t think we would allow that, and I don’t think the gaffer would allow it. We have all bought into it (the club ethos)."

In fairness to Brentford, and the same goes for John Egan who made the journey from West London to South Yorkshire last summer, both O'Connell and the Irishman have come-of-age in United's system which requires one to sit and the other to roam.

In Egan's case, although the £4m fee Wilder's employers paid to acquire his services now also appears a snip, his former club's modus operandi is based on recruiting players for relatively small fees and then selling them on at a profit.

United have also carved a niche in this particular market although thankfully, as O'Connell's extended deal proves, the flow of talent out of the club has stemmed following their return to the second-tier. Wilder, his assistant Alan Knill and head of recruitment Paul Mitchell have perfected the trick of spotting unfulfilled potential capable of flourishing in United's pioneering take on the 3-5-2 formation.

"We work on our shape all the time in training," O'Connell said. "The gaffer and Knilly are really big on that. They like pressing from a shape, not just everyone pressing, even though sometimes it might look like that."

"I am over the moon it’s got done," he continued, referring to his agreement. "It’s been a long time coming, since the summer. But it’s done now and I can just focus on my football."

Having challenged for the play-offs 12 months ago, United find themselves competing for automatic promotion after remaining on the coat tails of second-placed Leeds following last weekend's win over Rotherham. O'Connell, now in his third season with the club, traces that progress back to Wilder's manoeuvres in the transfer market, both in terms of the people he brings in and, perhaps just as impressively, the speed with which those who do not quite cut the mustard are moved on. 

"This squad is definitely better than it was last year," O'Connell admitted. "We have got really good experience, and that helps in the changing room, when you have experienced lads pushing us along.

"You have got players who have played at high levels, Gaz (Madine) who has played in the Premier League, (Martin) Cranie has played in this division for a long time, Ollie Norwood has made a massive impact, he has had promotions out of this league. It just works."

United travel to Elland Road on Saturday for a lunchtime fixture already being billed as an audition for the top-flight. But, like Wilder, O'Connell is aware of the damage any loss of focus against Brentford could cause.

"We are just concentrating on the next game," he said. "There’s a big thing about the Leeds game, but we haven’t even talked about the Leeds game.

"Brentford is the next game and that’s all we are focused on. It’s all about focusing on what we can do and taking care of business."