Dunfermline manager Stephen Kenny faced up to the pain of relegation on Saturday but claimed his improving side could have been a real force in the top-flight next season.
Kenny was bitterly disappointed by the 2-1 loss at Inverness which meant they will drop out of the Premier League this summer.
"It is very unfortunate for a club like Dunfermline with the ground that we have, the momentum of the last few weeks, getting to the cup final, qualifying for Europe and the potential which exists, that we have to go to the First Division," said Kenny.
"Had we stayed up then I think we could have done well in the SPL next season. It was cruel because we have played some outstanding football in the last few weeks."
Dunfermline looked set to take their quest to avoid the drop to the final day of the season next weekend, when Jim McIntyre volleyed them into a 37th-minute lead.
But goalkeeper Dorus De Vries fumbled Richard Hastings' free-kick into his own net and then substitute Rory McAllister's drive in the final minute of regulation time took a huge deflection off Sol Bamba to beat the helpless Dutch goalkeeper.
Dunfermline will play in the Uefa Cup next term after reaching the Scottish Cup final, in which they will meet SPL champions Celtic on May 26th. But St Mirren's 3-2 victory over Motherwell, coupled with defeat at the Caledonian Stadium, means Dunfermline will play in the First Division next season.
Two goals from Jan Vennegoor of Hesselink helped champions Celtic defeat Aberdeen 2-1 at Parkhead on Saturday to dent Aberdeen's hopes of a Uefa Cup place.
Steven Naismith's goal helped Kilmarnock defeat Rangers 1-0 at Ibrox yesterday.