In a low-scoring affair, both sides were run ragged throughout before the Saints extracted an unlikely three-point win over their 2009 preliminary final opponents.
The Saints, playing their third match in 12 days, were widely expected to tire late against a fresher Bulldogs outfit.
But as the Bulldogs repeatedly failed to capitalise on their opportunities, the Saints pounced with a surprise three-goal final term to seal the win.
“To come off two six-day breaks ... it shows the mental toughness of the group is obviously pretty good,” Lyon said after the match.
“And all credit to the conditioning staff ... they are obviously elite at what they do to give us the capacity to run out that game.
“The way we ran that out is a combination of the individual players and a combination of the (conditioning) program.”
Skill errors and poor decision making marred the Saints’ first half but the inability of the Bulldogs to take advantage of the pressure and turnovers they created saw St Kilda stay within striking distance.
Despite just two goals to half time and an avenue to goal through the Dogs’ zone looking unlikely, Lyon said he never doubted his side’s ability to emerge with a win.
“We wanted to go quick to avoid a bit of the press and we became a bit reckless and a bit chaotic and non-systematic,” he said.
“Once we gathered ourselves and started to use the ball better we had more (forward 50) entries and then the next part of the equation was to take advantage of that.
“It was a low-scoring game so you only really need one good quarter.”
The Saints now take on the in-form Carlton and after joining the chorus of coaches this season to remark on the evenness of the competition, Lyon said there was still a lot of improvement required from his side.
“We’ve got a lot to work on obviously and we’re still trying to find our system and the balance of selection ... there’s no simple quick fix,” he said.
St Kilda will enjoy a welcome nine-day break ahead of the clash but Lyon stressed he wouldn’t be putting too much stock into the extra respite.
“Sometimes you have the longer break and sometimes it just doesn’t pan out for you,” he said.
“We’ve just got our routine, we tweak and tailor that - it’s part science and part art form.
“It’s not an exact science and that’s why the best conditioners are highly sought.”
