The Baggies were assured of top-flight football minutes before the kick-off against Bradford City at the Hawthorns after third placed Sunderland only managed a 0-0 draw at Wigan.
"Gary Megson has done remarkably well as have the players and the coaching staff," Peace said.
"We really need to enjoy the occasion as there are precious few days like this."
A delighted Megson added: "It is a tremendous achievement to have won promotion with four games remaining.
"But now we want to go on and finish off the job by winning the title.
"There has been a lot of pressure on us to win promotion right from the start of the season so to have achieved our target is very pleasing."