Dan Biggar has been an 'unbelievable' Osprey - Brad Davis
|European Champions Cup play-off: Ulster v Ospreys|
|Venue: Kingspan Stadium, Belfast Date: Sunday, 20 May Kick-off: 15:05 BST|
|Coverage: Live on S4C, live on BBC Radio Wales AM, BBC Radio Cymru & BBC Sport website and BBC Sport app.|
Sunday's European Champions Cup play-off against Ulster will be Dan Biggar's 221st and final appearance in an Ospreys shirt.
The 28-year-old Wales fly-half is heading to Northampton Saints this summer, ending a career-defining decade with the region for which he has scored almost 2,200 points.
"He's been unbelievable," said Ospreys defence coach Brad Davis.
"To coach a player of that calibre has been an absolute privilege."
Davis added: "The characteristics that I really love about Dan is his desire to win everything, whether it be on the training pitch or on the field of play.
"He's an incredible competitor.
"I think everyone is fully aware of his influence on Welsh rugby and what he's given to the game in this neck of the woods."
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'Desire to win'
Davis believes Biggar has been even more influential since announcing his departure last September.
"After he signed his contract and announced he was leaving to go to Northampton, I think he became an even stronger acquisition for us.
"I can't speak highly enough of him as an individual and he's going to be missed."
Before joining Ospreys two years ago, Davis was a defence coach at Bath and Wasps.
Comparing Biggar to the fly-halves he has coached in the past, he said: "He's one of the most competitive that I've ever worked with.
"He has a fantastic kicking game.
"In terms of his pure desire to win, that he operates day in, day out, I think he's the best in that regard."
Davis was also full of praise for the departing Ashley Beck, who has been an Osprey since 2007.
The centre has made 150 appearances for the region and scored 30 tries, but will leave at the end of the campaign after signing a two year deal with English Premiership side Worcester Warriors.
"I think he's one of the smartest rugby players that I've been privileged to coach," said Davis.
"His understanding of the game is second to none. He's a very classy operator."
Beck has made seven appearances for Wales, and Davis says he should have won more caps.
"Unfortunately for Ashley, injuries have hampered what he has been able to do in terms of his stamp on the national game," he said.
"But in terms of his rugby IQ, it's as good as anyone I've known."