He came up with plays and concepts that would have NRL pundits drooling, more than three decades ago, in charge of an amateur team.
A vivid memory came from one Fox final against Otahuhu. After receiving the kickoff, McClennan had his team kick the ball straight back, over the on-rushing defensive line, pinning the surprised Leopards in the corner. The Lions forced an error, and scored soon afterwards. He was a constant innovator.
"It's fair to say sometimes the players were skeptical when he suggested some things at training," remembered second rower John Ackland. "But more often that not the opposition were thrown by it."
A pet play was having five eighth Shane Cooper receive the ball with his back to the defensive line on the fifth tackle, before kicking it back over his head for his teammates to chase. McClennan also pioneered the practice of halfbacks locking the scrum, and used the double dummy half ("mousetrap").
He would send his wingers sprinting down the sideline before a penalty kick for touch was taken, to catch the ball and force a quick restart. After complaints the rule was eventually amended. McClennan was the first of his era to bring in specialist coaches, and recognised the value of preparation before his peers. Some training sessions involved runs into the city, a workout at Clive Green's gym, before jogging back to Fowlds Park.
He was also a character. Ackland recalled turning up for a semifinal, only to find the Carlaw Park changing rooms covered in muddy water from the previous game.
McClennan raced upstairs to the boardroom, ripped up the carpet squares and returned to lay it down across the dressing room floor.
He also inspired numerous players to follow him into coaching, from Ackland and son Brian, to Tony Iro, Cooper, Dominic Clarke, Gary Prohm, Allen Hunt and Phil Beavers.
McClennan was a powerful winger in his playing days, picked outside Roger Bailey in the Kiwi's historic 24-3 victory over the Kangaroos in 1971. Like many of that era, McClennan worked in the freezing works.
"It was bloody hard but it toughened you up," McClennan told the Herald in 2012, "better than any gym workout I can tell you."
McClennan won more trophies with the Northcote Tigers before getting the St Helens job in 1990.
"He had to take on a great Wigan side, with all their resources, and more than matched them," said Ackland. Fans at Knowsley Road still remember another McClennan move, with giant forward John Harrison using a football style header to confuse the opposition.
"John was huge, about 6ft 7," recalled McClennan in 2012. "In a match against Sheffield we had him standing at dummy half. He picked up the ball, threw it back, and headed it into the in goal. [Kiwi] George Mann raced through to score, but there were three others queuing. The try was allowed as technically it was fine, though two weeks later there was a rule change."
McClennan's achievements — he also coached Tonga at the 1995 World Cup, where they were minutes away from upsetting the Kiwis — weren't always recognised in this country, but should never be forgotten.
