There are two reasons why the meeting of Saracens and Clermont Auvergne in the semi-finals of the Heineken Cup at Twickenham should attract a higher attendance than last season’s atmosphere-killing figure of under 26,000 when Saracens were beaten by Toulon at the same stage and the same venue.

The English club had been in discussions with European Rugby Cup Ltd about reducing ticket prices and creating family deals to make the most of the marketing time between now and the last-four tie on Saturday 26 April, even before Saturday’s eventful 17-15 win away to Ulster in the quarter-finals. The discerning rugby punter also ought to fancy watching the two most potent try-scoring teams from the Aviva Premiership in England and Top 14 in France. “A semi-final deserves a crowd of a minimum 40,000,” promised Edward Griffiths, the Saracens chief executive.

Chris Ashton reached a competition-leading nine Heineken Cup tries with a double at Ravenhill, and Saracens’ England wing is one behind the seasonal record, Sébastien Carrat’s 10 for the champions Brive in 1996-97. Ulster were left to ponder at woeful leisure the circumstances of Ashton enjoying his first-half splash-dive at the Aquinas End of the rebuilt red-and-white citadel in east Belfast, and his simpler dot-down of a lovely flat cross-kick by Owen Farrell at the Memorial End for a 17-9 lead with 66 minutes gone.

Jared Payne’s red card in the fifth minute for a dangerous tackle on Alex Goode, skewed the contest horribly. Ruan Pienaar might have plugged the huge gap Ashton sprinted into off a scrum if the Springbok hadn’t been labouring with a pre-existing shoulder injury.

“We thought that ill-discipline was the only thing stopping us putting together quite a good score,” said Brad Barritt, the Saracens centre, in attempting to summarise Ulster’s bloody-minded refusal to give in – Paddy Jackson’s two late penalties were counterpoints to Farrell’s uncharacteristic four misses that preceded his conversion of Ashton’s second try. “We have been to a quarter-final, a semi-final and the next logical step is to go one further and get to [the final in] Cardiff,” Barritt added.

The quarter-final was the 2012 loss to Clermont in Watford; the semi-final was a battering defeat by Toulon at Twickenham 12 months ago. As Saracens’ director of rugby Mark McCall put it: “You have got to earn your stripes in this competition, and the team we play next have earned their stripes more than most.”

The Payne sending off attracted furious debate – Goode was tipped up and over, even if there was surely no malice aforethought, and his fellow England full-backs Mike Brown and Nick Abendanon tweeted their support of referee Jérôme Garcès’ decision. A distraught Ulster captain Johann Muller felt a yellow card was more appropriate.

Clermont knocked out Leicester 22-16 in a 75th straight win at Stade Marcel Michelin, with Morgan Parra kicking 17 points, leaving Saracens as England’s last men standing in the Heineken for the third year running. Munster ejected the four-times champions Toulouse 47-23, with Keith Earls and Simon Zebo among six try-scorers for the Irish province.