Now there are four as Saracens take on Leicester Tigers and Exeter Chiefs face Wasps for a place in the Aviva Premiership Rugby Final on 28 May at Twickenham.
Both semi-finals are live on BT Sport 1 with coverage starting at noon on Saturday.
The reigning European Rugby Champions Cup holders, Saracens meet Leicester Tigers kicking off at 12.30pm.
Saracens have won their last eight matches in all competitions with their 13-21 defeat coming at the hands of Tigers in Aviva Premiership Rugby on 20 March. This is Saracens’ eighth appearance in the semi-finals and their seventh in succession. They’ve reached the final on four previous occasions in 2010, 2011, 2014 and 2015.
Tigers only Aviva Premiership Rugby away victory since the end of January was at closest rivals Northampton Saints on 16 April. This is Leicester’s 11th successive Premiership Rugby semi-final (they progressed directly to the final in 2005 after topping the table). Their only two defeats at semi-final stage have come in the last two seasons, at Northampton Saints and Bath Rugby.
Exeter Chiefs v Wasps kicks-off at 3.15pm.
This is the first time Exeter Chiefs have reached the semi-final stage in the competition.
Chiefs are the 11th different side to play in a Premiership Rugby Semi-Final and Sandy Park is the 11th different venue to host a semi-final in the competition.
Exeter’s only home loss in any competition since January 2015 came when Saracens were the visitors in Aviva Premiership Rugby in February 2016.
Wasps have made it to the last four for the first time since they were champions in 2008. Wasps only defeat in the last seven rounds of Aviva Premiership Rugby came when they visited Exeter on 1 May.
Wasps have participated in five previous Premiership Rugby Semi-Finals and the only time they haven’t progressed to the final was after a defeat at Sale in 2006.
Programme starts at noon on BT Sport 1:
Saracens v Leicester Tigers, kick-off 12.30pm
Exeter Chiefs v Wasps, kick-off 3.15pm
Rugby Tonight Extra – BT Sport 1 Thursday 6.45pm
Rugby Tonight – BT Sport 1 Monday 8pm