Formal word/phrase conveying the meaning of "top of your game"

In a story I'm writing, two of my characters have the following dialogue:

"We've both made mistakes in our approach."
"I share your sentiment, brother. It seems we're not at the top of our game today."

Using a phrase such as "we're not at the top of our game" seems inappropriate for the character in question, for he often likes to use flowery language in his dialogue. What would be a more formal way of conveying the same message in a single phrase/word?


Solution 1:

We're not at the zenith of our power[s].

zenith

/ˈzɛnɪθ/

noun

  1. the time at which something is most powerful or successful. "in 1977, punk was at its zenith"

synonyms: highest point, high point, crowning point, height, top, acme, peak, pinnacle, apex, apogee, vertex, tip, crown, crest, summit, climax, culmination, maximum, optimum, prime, meridian, flower; informal high noon

"the king was at the zenith of his power"

Google Dictionary

Also:

We're not at the apex of our abilities.

Solution 2:

Crowning moment - the triumphant culmination of

Crowning Glory The best and most notable aspect of something

"We've both made mistakes in our approach."
"I share your sentiment, brother. This has not been our crowning glory."

Solution 3:

Peak performance is the general formal phrase.

"We're not at our peak performance."

"We are performing at less than the peak of our ability", if the character is not only formal but also of the type to aspire to eloquence through ham-handed understatement and eschewal of brevity (like this sentence).