"ultimate partner" is a correct and usable phrase in written English.
It means the best or most ideal partner. Example: "My business thrived because I had found the ultimate partner in my colleague, who complemented my strengths and helped me overcome my weaknesses."
"Travel apps are the ultimate partner for smart watches.
But the ultimate partner for this sauce was crusty, roasted pork, which was the meat it was served with when I first tasted it in Spain.
These days, it's usually served with fish – indeed, chef Trish Hilferty describes it as "the ultimate partner for fish and chips", its salty sour flavours proving the perfect foil for the greasiness of battered haddock and fried potatoes.
To achieve customer success means to become the ultimate partner to your customers developing personal relationships, understanding each customer's unique needs, and implementing customer programs that help ensure customers gain meaningful value from your solutions.
A sophisticated blend of form and function, this special Limited Edition reflects the individuality and discerning style of both car and driver – the ultimate partner for the perfect drive.
You may have your disagreements (likely a lot of disagreements), but they can also be your ultimate partners-in-crime.
Mr. Soto, a principal dancer with the New York City Ballet, was cited as "the ultimate dependable partner" who "is also known for his sensitivity and responsiveness to his partners".
Janice Cartin is called the ultimate silent partner who fully understands her husband's obsession.
So can he achieve consensus with President Obama, his ultimate negotiating partner, on reducing spending and raising more revenue?
In this zombie world of ours, they are your ultimate kickass partner.
And in the too-brief sequence in which they meld as an iconic dance-floor couple, they approach the swooning grace of Fred Astaire and Cyd Charisse, whom the movie holds up as ultimate dancing partners afloat in pure rapture.
