Celtic League: Friday, April 8Cardiff Blues 8 Ulster 22, Arms ParkScorers: Cardiff: Tries: Robin Sowden-Taylor, Tom Shanklin, Craig Quinnell; Cons: Nick Macleod 2; Pen: MacleodUlster: Try: Tommy Bowe; Pen: Paddy Wallace
The late injury withdrawals of experienced duo David Humphreys and Tyrone Howe saw Ulster at a loss from the kick-off - knocking on initially as Wales flanker Robin Sowden-Taylor nipped in for a first-minute try.
His effort - touched down after only 49 seconds - was officially credited as the fastest try in Celtic League history.
Cardiff full-back Nick Macleod converted and tagged on a penalty before missing the extras of centre Tom Shanklin's score.
Ulster fly-half Paddy Wallace negated their slow start as a well-judged break from the Ballymena man set up Bowe's try reply.
Wallace secured a close-in scrum for McCall's charges and with the ball ferried out to Bowe, the 21-year-old had enough pace and power to get past Shanklin and bag his eighth league try of the season.
Wallace - although reducing the arrears to 15-8 on the restart with his second penalty - missed a further two shots at the Blues' posts and home captain Martyn Williams set up lock Craig Quinnell for the crucial score in the closing stages.
Currently eighth and in the last of the Celtic Cup quarter-finalist positions and pole position for Heineken Cup qualification, Ulster entertain the fourth-placed Scarlets on Friday night in their final league tie.
McCall - whose side have won their last five league outings in Belfast - admitted: "It's our last league game and it is vital we get the victory. The important thing is it's in our own hands and we are not relying on other results.
"Qualifying for the Heineken Cup is essential but getting into the Celtic Cup would be good as we are holders and want to retain it.
"Once you qualify you're only three games away from winning it."
Ulster lifted the Celtic Cup in December 2003 - beating Edinburgh 27-21 in a comeback win at Murrayfield. Fly-half David Humphreys - an injury doubt for the Scarlets clash, due to a hamstring strain - kicked 17 points in the final.
Cardiff: Nick Macleod; Chris Czekaj, Rhys Williams, Tom Shanklin, Craig Morgan; Nick Robinson, Ryan Powell; John Yapp, Gareth Williams, Gethin Jenkins, Craig Quinnell, Robert Sidoli, Robin Sowden-Taylor, Martyn Williams (Capt), Kort Schubert.
Replacements used: Tristan Davies for Shanklin (38 mins), Nathan Thomas for Schubert (68). Not used: Ben Evans, Rhys Thomas, Nathan Budgett, Ma'ama Molitika, Dean Dewdney.
Replacements used: Ronan McCormack for Moore (32 mins), Rowan Frost for Longwell (50), Adam Larkin for Wallace (57), Andrew Maxwell for Young (72). Not used: Nigel Brady, Campbell Feather, Neil Doak.
HT: Cardiff 15 Ulster 5; Attendance: 5,600Referee: David Changleng (Scotland)