Moeen Ali accused Wayne Parnell of being "almost resigned to losing" before conceding the boundary that allowed Essex to depose Worcestershire as Vitality Blast champions at a sold-out Edgbaston.
Worcestershire's bid to become the first team to successfully defend the domestic English Twenty20 crown fell flat as, with two runs required from the last ball of the final, Parnell conceded a boundary off Simon Harmer.
Essex were therefore left celebrating a thrilling four-wicket victory after overhauling Worcestershire's 145 for nine to leave Moeen questioning the mindset of Parnell in the crunch situation.
Parnell had earlier held his nerve when presented with an identical scenario from the last delivery of the semi-final against Nottinghamshire, bowling a dot ball as Worcestershire claimed an improbable one-run win.
But after Essex captain Harmer had bludgeoned Parnell back over his head from the penultimate ball of the final, Moeen believes the South African left-armer was unable to recover.
The England all-rounder said: "I told him 'you've done it before so you can do it again'.
"In my opinion, his body language showed that he was almost resigned to losing. I still think you can win those games because it's not easy, actually, when you need one to win, to try to belt it.
"For the group of guys who are down in the changing room downstairs, the work that they've put in, the human beings that they are, they deserve absolutely everything, and as Essex always does, we'll celebrate properly."
Victory marks the start of what could be a memorable few days for the club, who only need to avoid defeat at Somerset next week to clinch the Specsavers County Championship pennant.
Harmer added: "I definitely think we'll be able to celebrate. It's not often that moments like this come around and I think you need to enjoy them, we can pay for the consequences tomorrow!
"I don't think we'll go nuclear but we'll definitely enjoy tonight."