|European Challenge Cup|
|Date: Sunday, 4 April Kick-off: 20:00 GMT Venue: Twickenham Stoop|
|Coverage: Listen to live commentary on Foyle DAB and the BBC Sport website|
Nick Timoney feels he has never been in a better position to help Ulster end their long chase for silverware.
The 25-year-old has grown from fringe player to established back-row regular in recent seasons and is ready to play a major role in the trophy hunt.
"I have found a good bit of form and this is the most consistent run I've had," said Timoney.
Ulster play their first ever Challenge Cup tie on Sunday away to Harlequins, who have named an understrength side.
For a lot of Timoney's career, he has been Ulster's second-choice number eight behind Coetzee, who was named on Thursday as the PRO14 Players' Player of the Season.
Coetzee misses Sunday's game through an injury which may prevent him for playing for Ulster again before returning to South Africa in the summer to join the Bulls.
Timoney is capable of playing anywhere across the back row but enjoys number eight and would like to make that position his own.
"Obviously there's going to be opportunities but it wasn't a case of somebody calling me over and saying 'he (Coetzee) is leaving, you can take this'," Timoney said.
"Me and Marcell have played together this season but his announcement about leaving (in December) came at a time when I'd hardly played in two or three months.
"I had a bit of a chip on my shoulder.
"There was a while when we were both sort of playing number eight, he was the first choice and I was the second choice but I wasn't involved a whole lot.
"His leaving is a chance, there's always chances, and it's about timing but it wasn't planned that way."
Timoney has made 10 appearances for Ulster this season and if they get beyond 'Quins, whose team selection suggests they are prioritising domestic matters ahead of a tilt at European club rugby's second biggest prize, they will be strongly fancied to win it.
Denied an opportunity to play knockout rugby despite an excellent run of results in the Pro14 this season, Ulster will channel their frustrations into the forthcoming Challenge Cup and Rainbow Cup competitions.
A two-time Leinster Schools Cup winner with Blackrock College, Timoney will be a key player in that charge.
"This is the most consistent run I've had for a while. I'm enjoying knowing what I need to do and what I need to bring each week.
"I like to think I'm adding to the team. I've found a good bit of form and have that bit more experience now.
"To have the season we did and not really get the reward for it in terms of play-off rugby in the Pro14 was obviously frustrating.
"It's good to have the two competitions that are short and sharp and straight in at the deep end to get all that energy and frustration out and see what we can do."
Harlequins: Green; Northmore, Lang, Lasike, Earle; Herron, Steele; Garcia Botta, Elia, Collier, Tizard, Hammond, White, Kenningham, Lawday (capt).
Replacements: Head, Els, Kerrod, Cavubati, Jurevicius, Stafford, Tapuai, R Chisholm.
Ulster: Lowry; Baloucoune, Hume, McCloskey, Stockdale; Burns, Cooney; O'Sullivan, Herring, Moore, O'Connor, Treadwell, Reidy, Murphy (capt), Timoney.
Replacements: Andrew, Warwick, O'Toole, Izuchukwu, Rea, Mathewson, Madigan, McIlroy.
Referee: Romain Poite (France).