The most common and most likely answer to this crossword clue is the 11 letter word GRANDMASTER
I've seen this crossword clue in The Times
G
R
A
N
D
M
A
S
T
E
R
More clues leading to the result GRANDMASTER
- One well qualified to get a mate?
- Skilled gamer is smart when playing with danger
- Exceptional player originally made bloomer on piano
- One achieving great success across the board
- Top chess player, magnificent teacher
- An exceptional player and a student leave a floral arrangement in front of the pole with hesitation
- Expert at managing men on board?
- Two monkeys together? Learn one successfully seeks mates
Buddy explains!

The straight part
We know that "One well qualified to get a mate" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one well qualified to get a mate = grandmaster.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does GRANDMASTER mean?
GRANDMASTER noun- A player of the highest rank, as determined by FIDE, with an Elo rating of at least 2500.
- A master in a field, whose skills or accomplishments exceed those of other masters.