"I couldn't have wished for any more on a personal level, but winning the league would cap it all," said McDonald. "It will be doubly hard next season because I'll have to do it again."
The former Motherwell player squandered an excellent chance against Hibs on Saturday with the game still in the balance.
"Every good striker has that little selfish streak in them, although I got myself out of a hole today.
"I definitely should have cut it back to Mark Wilson when I went round the keeper and at 1-0 I was hoping it didn't come back to hurt us. I was glad that I redeemed myself.
"The goals are great, but they will mean a lot less to me if we don't win the title."