Paris - Ulster stunned two-time winners Munster on Sunday, beating them 22-16 in their European Cup quarter-final -- the hosts first home defeat in any quarter-final in all competitions.
Former Springbok international Ruan Pienaar contributed 15 points with his boot to give Ulster only their second win at Thomond Park in 20 years and a semi-final date in Dublin with another surprise winner from the quarter-finals Edinburgh, who beat Toulouse on Saturday.
The only previous time Ulster reached this stage they went on to win the trophy in 1999.
Champions Leinster - who thrashed Cardiff on Saturday - will play the winners of the final quarter-final between Saracens and Clermont.
Munster, who were bidding for a record 10th appearance in the semi-finals, were left reeling by their opponents as Ulster stormed into a 16-0 lead after just 20 minutes.
Pienaar punished them for their ill-discipline landing two penalties from inside his own half before a brilliant individual try by 22-year-old wing Craig Gilroy.
A quick passing movement found him on the left wing but inside his own half, before he showed an electrifying burst of speed to outstrip first his opposite number Denis Hurley and then break another three tackles to touch down.
Pienaar had no trouble adding the conversion and then slotted over another penalty in the 20th minute to make it 16-0.
Nothing was going right for Munster at this stage with elementary mistakes being made by even their most experienced players such as Ronan O'Gara.
Ulster, though, could do little wrong and flyhalf Ian Humphreys, son of former Ireland flyhalf David who inspired Ulster to the 1999 trophy, dropped a goal from a long way out to make it 19-0.
Munster, though, showed the patience and nerve that has served them so well down the years as Simon Zebo scored his fourth try in five European Cup appearances after shrugging off a despairing tackle by Andrew Trimble to touch down in the corner.
O'Gara put over a brilliant conversion from the touchline for 19-7 and things swung back further towards Munster when Ulster flanker Chris Henry was sin-binned in the 37th minute.
Indeed the hosts went in just nine points in arrears as O'Gara slotted over a long range penalty right on half-time to leave the game in the balance.
O'Gara landed another penalty early in the second-half to take the hosts within a converted try of taking the lead.
However, the faultless Pienaar converted another penalty with just over 20 minutes remaining to make it 22-13; record points scorer in the competition O'Gara added one of his own a on the hour mark to make it 22-16.
Pienaar, though, was found to be fallible when he had a chance to put the game beyond the hosts in the 75th minute but for once he missed. However, it was not to matter as they held out for a famous victory.