The Robins manager was still covered in champagne when attending his post-match press conference having been out on the pitch with his players to collect the trophy.
And after seeing a hat-trick from centre-back Aden Flint, which took his goal tally for the season to 15, during the 8-2 thrashing of the Saddlers, Cotterill was bursting with pride over the achievements of his squad this season.
“The players have been magnificent all season and that 30 or 40 minutes after the game will live with them forever,” said Cotterill, whose team also won the Johnstone’s Paint Trophy at Wembley.
“I am not one to show excitement by jumping around, but I felt a real warmth at making so many people so happy. The supporters have made a huge contribution this season, as has everyone associated with the club.
“We weren’t at our best in the first half and Walsall came to make a real game of it. But I knew we would score goals today if we played as we can.
“There is a need to strengthen the squad for next season, but not with the urgency of last summer. It will be hard to improve on the players we have in so many positions.
“I haven’t discussed a budget yet and I am looking forward to a break before preparing for the move into the Championship.”
Walsall led through Jordy Hiwula’s 12-minute shot, but City were ahead within nine minutes as Flint volleyed an equaliser and Jay Emmanuel-Thomas slotted home a penalty after handball by Kieron Morris.
The Saddlers showed plenty of enterprise to level before the break, with Hiwula shooting his second through the legs of Luke Ayling after 35 minutes.
But City ran riot with four goals in 10 minutes after the interval, Kieran Agard sparking the avalanche with a low shot from Korey Smith’s 57th-minute pass.
Emmanuel-Thomas teed-up Marlon Pack to make it 4-2 and then blasted the fifth himself before Flint took his goal tally for the season to 14 by stabbing in a Luke Freeman cross.
It was Flint again completing an unlikely treble by volleying in substitute Wade Elliott’s cross at the far post four minutes from time before Agard completed the rout in injury time from Smith’s through ball.
Walsall boss Dean Smith admitted: “I am angry and embarrassed. We folded after City’s third goal and that is not like us.
“I’m just sorry for our young keeper Craig MacGillivray because he didn’t stand a chance with any of the goals. I just hope the experience doesn’t scar him because he certainly wasn’t to blame.
“I have some contract negotiations coming up with some of the players and this has given me something to think about.
“In fairness, they have done well this season, but today we conceded some very poor goals, having competed well for an hour with the deserving League One champions.”