"a last try" is correct and usable in written English.
You should use it when you are referring to one last attempt at something. For example, "She had already given up, but I convinced her to give it a last try."
This may be a useful qualification for heading a grand coalition, a configuration last tried, with limited success, in the late 1960s.
In fact, they scored the last try, a clever if unfancy charge-down and follow-up by Sam Cordingley.
In September, the United States Supreme Court will consider hearing an appeal the environmental groups filed after losing in their last try at a federal appeals court.
He dragged the boy onto his surfboard, made a few last tries to find Shawn, and then began swimming back.
Lotus have both cars set up in long-wheelbase trim, a specification last tried - but not raced - at the Italian Grand Prix a month ago.
"I think the last try was a bit cruel but other than that there were a lot of positives to come out of this game.
A day later, making one last try, I called him.
"We addressed it in the second half but the last try was a frustrating one.
I was a bit disappointed with the last try, we could have kept that one out".
If it fails until the very last try on a 4-digit password, that's 4.5 days of bruteforcing.
