Owen Farrell vs Paddy Jackson
The out-half battle this afternoon will be fascinating to watch as two in-form 10s go head-to-head.
Both 24-years-old, both top scorers for their sides in this season's competition and both integral to the way their two coaches look to play rugby, there are plenty of similarities between the pair.
Neither will have enjoyed the World Cup, Farrell a controversial selection during England's ill-fated campaign while Jackson spent most of the tournament watching on, but much has changed since then.
With Farrell's improved form central to Saracens table-topping run, he is sure to be at out-half when England face Scotland next month while Jackson has seemingly jumped ahead of Ian Madigan to put pressure on Johnny Sexton.
While Jackson's flat passing and willingness to approach the gainline are two key attributes in bringing Ulster's talented backline into play, Farrell is a high-end game manager capable of exerting great levels of control.
With a 4G surface offering the chance for a high tempo game, Ulster management have stressed the need to play with a larger degree of control than they managed in the early stages of last week's struggle against Oyonnax.
Parity up front will be more than important than ever with the returning Wiehahn Herbst's battle with the destructive Mako Vunipola sure to be crucial in the set-piece.
With Farrell usually so reliable with the boot, admittedly having failed to show it during his last two games against Ulster, the visiting side's discipline will have to be exemplary.
Where the threats are
Ulster have already gained first-hand experience of Saracens' strengths this season when the English champions took a bonus point home from Kingspan Stadium back in November.
Matters have improved immeasurably for Les Kiss's men since then, but there is still plenty for them to be wary of.
Mark McCall's squad, having lost for the first time this season only last week, have overhauled mega-rich Toulon as favourites to lift this trophy in Lyon come May.
With threats all over the park, the Vunipola brothers, Itoje and Jamie George will make the hard yards in the pack, but their pragmatic style still allows for a dangerous back-three to make an impact.