Upsets. Cup upsets. Even the ugly portmanteau that is 'cupset'. It's what knockout competitions are all about. Football's history is rich with them; Ronnie Radford, Micky Thomas, York winning 3-0 at Old Trafford, Sunderland beating the mighty Leeds United at Wembley. But it's not just the round-ball game that has its storied glories of the underdog giving their supposed superiors a bloody nose.

Sheffield Eagles were formed in 1984 and not a lot happened after that. After starting life at the old dog racing stadium at Owlerton, they entered a nomadic period following the publication of the Taylor Report which left the venue deemed as unsafe, touring the city and further afield with games hosted at Hillsborough and Bramall Lane as well as Barnsley FC's Oakwell and Wakefield Trinity's Belle Vue. However, despite not having a place to call home, they got their first taste of top-flight rugby for the 1989/90 season.

When Sheffield won the right to host the 1991 World Student Games, the Don Valley Stadium was erected and, in September 1990, it became the permanent home of the Eagles. Relegated back to the Second Division, their first season at the ground saw them win the league and promotion back to the big league which they began to establish themselves in.

Everything changed in 1996. The dawn of Super League and the switch to summer was the biggest upheaval in the game since the 1895 split with rugby union. Mergers were mooted – in Sheffield's case with Doncaster to form a South Yorkshire franchise – but dropped after fan protests. So it was that the Eagles became founder members of the new league and kicked off the new era in Paris, losing to the newly formed Paris St Germain.

Despite the league switching its season, the Challenge Cup remained in its old slot for some time with the final played on the weekend of the May Day bank holiday. The 1990's were Wigan's. Much of the 1980's had been as well. Their run of eight successive Cup wins came to an end in 1995, but they were still a formidable outfit. After local rivals St Helens won in 1996 and 1997, Wigan started the 1998 campaign by blasting away both Keighley and Dewsbury without conceding a point, racking up over 130 themselves. A showdown with the Saints loomed in the quarters, but Wigan were too strong, winning 22-10. London were no match in the semi-finals and Wigan were back at Wembley, ready to make amends and get their hands on 'their' trophy once more, especially as most of the other Super League clubs had been busy knocking each other out. Castleford took care of Leeds and Bradford, St Helens doing likewise to Warrington.

Sheffield, meanwhile, dispatched lower-league Leigh 66-11 in the fourth round before taking one of the last two remaining amateur sides in the competition in the fifth, Egremont Rangers having shocked Workington Town 18-0. There would be no further shock as the Eagles showed no mercy, winning through 84-6. Drawing Castleford in the quarters proved a much harder task, but in front of a partisan Wheldon Road crowd, they won through 32-22 and marched on to the semi-finals where they would face Salford. Two years previously, when still outside the top flight, Salford had been the ones to end that run of Wigan victories and were not to be taken lightly, even more so when they raced into an 18-0 lead after 20 minutes. Digging deep, Sheffield clawed their way back into the game. The big prop forward Dale Laughton popped up late on with the clinching try that sent the Eagles to Wembley 22-18.

“No-one ever gave us a chance, we thought John [Kear, the coach] was mad when he came into our first pre-season training camp and said 'we're going to Wembley and we'll win it'”. The words of scrum-half, inspiration and Mr Sheffield Eagles, Mark Aston. A Castleford lad, Aston chose to sign professionally for Sheffield despite interest from his home-town club. He'd go on to make 389 appearances for the club spending just the 1994/95 season anywhere else when he spent a year at Featherstone which took him to a Challenge Cup semi-final.

“No-one was going to beat us on that day without a fight”, Aston recalls. “We were outstanding. I remember standing in the tunnel with Johnny Lawless, the hooker from Siddal, in the background shouting '1998, the year of the Eagles' and you looked at the Wigan players glancing at us thinking 'are they kidding themselves?” That Wigan line-up featured greats such as Andy Farrell, Jason Robinson, Gary Connolly, Henry Paul, Kris Radlinski – they were unbackable favourites. What Sheffield countered with was a fierce team spirit. Aston continues; “People would have needed to shoot us down dead to beat us that day, and Wigan threw everything at us, but we were just resilient, we had the desire and the commitment, togetherness to make sure we did whatever it would take. And that was something of a bond that players, the group and the coaching staff all bought into in the early days leading up to the final. It was a mental strength that we had built over that period.”

The Eagles flew out of the blocks and took the lead off the back of a huge bust by Australian back-rower Paul Carr in just the fourth minute. Aston kicked wide and winger Nick Pinkney plucked it from the sky to open the scoring. Winger Matt Crowther got over in the opposite corner on the half-hour, Aston again heavily involved. Aston then added a drop-goal late in the half to go into the break leading 11-2, Wigan's only response a penalty goal.

The lead went out to 17-2 early in the second half as Darren Turner battled his way through to score under the posts. Back came Wigan with Australian winger Mark Bell pulling a try back with Farrell converting for 17-8. And Farrell thought he'd brought them back closer still with 15 minutes to go, but referee Stuart Cummings ruled he'd not grounded the ball. The Sheffield rear guard was working overtime by this point, but when mercurial Kiwi journeyman Dave Watson cut down Tony Smith as he looked set to score, suddenly it looked like the Eagles were going to make it.

“Nobody believed we could do it apart from us”, said Captain Paul Broadbent. He and Laughton battered the Wigan line time after time, laying the platform for Aston to work his magic in a man-of-the-match performance. “It's was a massive achievement that still fetches a smile to my face, you get a glint in your eye knowing we achieved something against massive odds,” said Aston. "It's something nobody can ever take away from us, you have dreams of playing professional rugby league, playing for your country and you want to play at Wembley, and that group of 1998 certainly did that.”

The glory was short-lived. One year on from that victory and with the expected upsurge in numbers following Wembley glory not materialising, the club was in trouble. With the Eagles set to fold, the RFL put feelers out for clubs to merge as they looked to reduce the size of Super League. Gateshead, also struggling in something of a Rugby League outpost, 'merged' with Hull, all trace of the Tyneside club being washed away in the process. Sheffield 'merged' with struggling Huddersfield under the unhappy banner of 'Huddersfield-Sheffield Giants' and playing game in Huddersfield's kit and Huddersfield's stadium. Three season tickets were sold to address with an S postcode. That the Sheffield part of the name disappeared after one season told you how much of a merger this actually was.

Once again, the man to the rescue was Aston. Between the end of the 1999 season and the start of 2000, he set about reforming Sheffield Eagles, taking over as player-coach. In 2004, he finally hung up the boots and took over from his father as CEO of the new club, hiring Gary Wilkinson as head coach. When Wilkinson resigned unexpectedly after gaining promotion to the second tier, Aston once again filled the breach, a position he holds to this day. Mr Sheffield Eagles.

With the Don Valley Stadium a millstone round the neck of the city, it was pulled down in 2014. The Eagles moved back to revamped Owlerton. The circle was complete, but how high those Eagles briefly soared.

John is @johnnydobbo.