Deceived by flattery?

[RonWatson]

I've come across the phrase 'flatter(ed) to deceive' recently, and am having the hardest time grasping its concept. A quick Google search shows that a) it's a popular sporting term, b) can describe a strong squad that fails to live up to its hype (...squad have shown promise in flashes, but have flattered to deceive), or c) a description of a winning team (Holders France flattered to deceive with a momentous 2-1 win over England.) Anyone? Thanks in advance....

[Marsh]

The OED gives, among other meanings, "To inspire with hope, usually on insufficient grounds."
A quotation it gives in this section is "Two furlongs from home Maiden Erlegh looked most dangerous but he flattered only to deceive."
Hope this helps.

[Marsh]

Defining "flatter", the OED gives, among other meanings ...

[aRonWatson]

Perfect, Marsh! Makes sense now. Thanks for that.