MELBOURNE, AUSTRALIA - AUGUST 29: Luke Ball of the Magpies handballs during the round 23 AFL match between the Collingwood Magpies and the Hawthorn Hawks at Melbourne Cricket Ground on August 29, 2014 in Melbourne, Australia. (Photo by Quinn Rooney/Getty Images)

Former St Kilda coach Ross Lyon has revealed a deep regret that may have cost his side their first premiership since 1966.

In an interview with Damian Barrett on The Coach, Lyon admitted trading Luke Ball to Collingwood at the end of 2009 may have been a major factor in their failed chase for a flag.

Lyon conceded that Ball’s departure may have led to the Pies receiving significant inside information on his sides tactics and would have played a part in the Pies’ 2020 premiership victory of the Saints.

“He took some IP (intellectual property), with Max Hudghton (as an assistant coach) to help teach the press to Collingwood, and their talent was very strong,” Lyon said.

“Clarko (Hawthorn coach Alastair Clarkson) started that mobile grid and we did a bit of work and turned it into a strong press, and Collingwood hadn’t done it very well in 2009, but in 2010, they became good.”

“I could see the St Kilda peoples’ works, and Clarko’s as well, and they adjusted very quickly and they became a great defensive team as well.

“It was a fine line, wasn’t it (the Saints drew with the Pies in the Grand Final of 2010, then got belted in the replay)? They dominated (the replay), they were the best team the whole year.”