There was a time when the Challenge Cup almost became the personal property of the Agar family. Allan Agar won the trophy as a Hull Kingston Rovers player in 1980 and again as coach of Featherstone Rovers in 1983 after one of the great Wembley upsets.

Each time it was brought to the family home, his sons, Richard and Jonny, would gather their friends for a game and the chance to lift the cup, which they would fill with cherryade and prop up in the back garden.

A quarter of a century separates the pit villagers of Featherstone under Agar Sr and their improbable defeat of Hull's city slickers from Richard Agar's attempt, ironically as head coach of Hull, to overturn arguably equivalent odds in tomorrow's final against St Helens, cup winners six times in the past 12 years. No father and son have coached in a Wembley final before, although Agar Jr did win the trophy he held aloft as a child when, as Hull's assistant coach, they upset Leeds Rhinos in 2005.

“The two times my dad won it are ingrained in me,” Agar, 36, said. “I was 8 when it was brought home the first time and 11 when he led massive underdogs in Featherstone to victory, staved off relegation and won the Man of Steel award for 1983. You go in the pubs around Featherstone and the photos of that day at Wembley are still there and those players are still revered. The cup was a huge part of our lives. The difference is I'm now at the epicentre of it.”

As for any fatherly advice, Agar said: “No, not really. He's organising his usual Wembley trip. He's got more important things on his mind, like getting his quiz together for the train, so I don't want to trouble him with my worries.” Any sentiment is reserved until after the match. “Of course it's a big thing, the first father and son to coach cup final teams, but I've had no time to dwell on it,” he said. “It probably struck home walking down the steps with a minute to go in the semi-final against Wakefield. I didn't realise my dad was sat a few rows in front. Obviously, he was pleased and quite emotional. You can't get away from Saturday being a special day.”

Agar has briefed the foreign players in his squad on the competition's historic significance and insisted that wives, girlfriends and families are an integral part of the weekend. “We know where the focus is and the players and coaching staff are not there for their jollies,” he said. “But if you can't enjoy being in a cup final and the challenge we face, what can you enjoy?”

The suspicion that Hull may just be grateful for reaching the final, after a fraught season of injuries, furore of twice fielding an ineligble player in the early rounds and upheaval, with Agar becoming the club's third head coach in three years after Peter Sharp's dismissal in May, has prompted fears of a runaway St Helens victory. Naturally, Agar does not view it that way.

“St Helens have been there and done that since 1996, but we like playing them. With Saints, it's less of an arm wrestle. You get the opportunity to play. You've got to take those chances.” If so, it will be champagne, not cherryade, filling the cup.

Relatively speaking

Gus Risman captained Salford against Barrow in the 1938 final and led Workington Town to victory over Featherstone Rovers in 1952. His son, Bev, helped Leeds to victory with four goals against Wakefield Trinity in 1968.

Clive Sullivan was a winner with Hull KR in 1980. His son, Anthony, triumphed with St Helens in 1996 and 1997.

New Zealand brothers Kevin and Tony Iro amassed six winner's medals with Wigan from 1988 to 1991.

Two sets of brothers have won the Lance Todd Trophy for man of the match. Neil (Wakefield 1962) and Don (Wakefield 1968) Fox, and Robbie (Bradford 1996) and Henry (Bradford 2000) Paul. Keiron Cunningham, who plays in his eighth final tomorrow, is still attempting to make it a third set, by emulating his eldest brother, Eddie (Widnes 1982).