Leek said focussing on her horses had taken away family pressures as husband John is sidelined through disqualification and unable to currently stay on the family property.
"I think I've been lucky to have this focus," Leek said.
"It's been tough on the family, and I have just focussed on my horses and that is what has got me through."
Cosmic Crusader had not raced beyond 1800m prior to Saturday and handled the distance rise without a query.
Leek said the former Perth galloper had race fitness on his side.
"I just think, I shouldn't say it, but he was the fittest in the field," Leek said.
"He's had a few runs now, I thought he had come on from the last run, and I just thought he would run the 2000 (metres).
"He's a tricky horse but I sent a message to Bob (Peters) this morning, (saying) there's no excuses today.
"He's spot on and thank God I was right."
Saturday's outing was the first time Cosmic Crusader had seen a heavy track, although he had won five times from six starts on soft tracks.