Look at their best cup finals
1996 - Keane, nothing spectacular but dominated the game. Redknapp and Barnes didn't a kick -
2001 - Viera dominated a young inexperienced SG (I'm not holding this against SG in this debate) and dominated the game. If Owen hadn't sprung up he'd have easily been man of the match (he might have been anyway). Excellent performance to control the game.
2006 - SG didn't control the game against West Ham, it was end to end stuff. However, his great last minute goal will never be forgotten and his first wasn't too bad either.
Dominating a game versus vital goals is the real difference.