Horan came on as a 54th minute replacement for du Preez at the Sportsground and on the basis of his impressive 26+ minute shift retains the number 1 shirt a week before the Heineken Cup quarter final.
Mick O'Driscoll and Donncha O'Callaghan partner up for just the third time this season, O'Callaghan playing in his 101st League game while winning his 198th Munster cap and he readily admits this is one of the games that sets his pulses racing.
" Absolutely. These are the games that everyone wants to be involved in." he said after training yesterday in CIT. "They're what make the dark and dirty nights of winter training so worthwhile.
"And they're great occasions. There's always that bit of a bigger buzz ahead of the Leinster game.
"It'll be a massive game for us," he continued. "They're the form side, a real good side and they'll have all their big boys back so we'll really have to produce something special if we're to get anything out of this."
News of injured trio Paul O'Connell, Donnacha Ryan and Conor Murray is positive.
Ryan took a limited part in training yesterday while O'Connell and Murray travelled to Dublin to see a Specialist who cleared them for training next week.
Ryan would look to be on track for inclusion in the squad for the Ulster game while O'Connell and Murray's participation will depend on how they come through training.
Munster: F Jones; J Murphy, K Earls, L Mafi, S Zebo; R O'Gara capt, T O'Leary; M Horan, D Varley, BJ Botha; D O'Callaghan,M O'Driscoll; Dave O'Callaghan, P O'Mahony, J Coughlan. Replacements: M Sherry, W du Preez, S Archer; B Holland, T O'Donnell, D Williams, I Keatley, D Barnes.