Steve Evans told Millwall to enjoy life in League One after Rotherham United secured their Championship status on the back of claims made by their rivals.
Rotherham overcame a three-point deduction handed down last week for fielding an ineligible by defeating Reading 2-1 on Tuesday, which ensured the club's survival and relegated Millwall and Wigan Athletic.
Tuesday's triumphant day was sweetened by recent comments made by Millwall striker Lee Gregory, who was hoping Rotherham would "bottle it" after throwing away a 3-1 lead to draw 3-3 with Derby County last week.
"A Millwall player said we've not got bottle. I've got 12 bottles of pink finest Champagne and we'll be drinking them for about a week," said Evans.
"Look forward to League One, son, and keep your trap shut."
Evans added: "When you get points taken away from you it's a bombshell but we had to show resolve, and character and we have done that.
"We have got over the line and they can take our points but they will never take our fighting spirit and passion to stay in the division.
"I have won a lot of promotions and been at Wembley and won the play-offs, I think individually, this was the biggest result.
"In terms of being relieved, we thought we were over the line after Brighton. This for me was bigger than Wembley.
"Winning and keeping them up is the biggest achievement for me.
"This was always going to be the hardest task, now the ambition is to build on that.
"I am very proud of the football club. We have not got everything right, we have had to work tooth and nail to say in this competition, because there are some wonderful clubs."
