The Saracens empire is at an end; the Saints go marching on. On a raucous night in Northampton where Cinch Stadium at Franklin’s Gardens rocked with an intensity and fervour seldom sighted in English club rugby, the hosts denied Owen Farrell a last tango at Twickenham with a performance that showcased their champion qualities.

All season long Northampton have led the way with brilliance and brawn but this represented a test of their bottle, serial winners in town with every reason to make these last weeks with Farrell and co count.

But there is something different about these steely Saints. So long the valiant entertainers in this competition, Phil Dowson’s side have added steak to their backline sizzle: bigger, beefier and brighter too. Thrice this season Saracens have tried and failed to beat them, falling two points short here as Northampton held firm at the last after two late tries had given the visitors hope.

It is a clean sweep that could represent an epochal change. Bath or Sale will represent stiff final opposition but such is the age profile of this Northampton team that you would suggest they will be back for more and more. With Fin Smith steering the ship, Tommy Freeman becoming the most complete back in the country and Tom Pearson reminding everyone of his considerable qualities, here is a core to rival that which Saracens are losing.

A night laden in narrative had nonetheless been dominated by talk of two men, Courtney Lawes and Farrell battling for the final time in English rugby. There would be room for only one to write another chapter at next week’s final. They emerged at the head of each line, leaders and legends of these proud clubs steering their sides through the smoke and into battle. Cinch Stadium at Franklin’s Gardens crackled with excitement for a first semi-final in these parts since 2015.

The two sides traded blunderbuss shots to open, the physicality high from the off with Sarries’ heavy mob repeatedly knocked back. Both sides had loaded up with six forwards on the bench in recognition of the likely physicality, and it was Northampton’s back five that made the early statements with a series of crunching hits.

Christophe Ridley’s whistle, though, brought more comfortable progress for the visitors and – with Farrell and his strapped right quad excused from kicking duties – Elliot Daly stepped up to slot the opening three. The full-back soon added another from further out.

Defences had dominated the first 20 minutes yet Saints (as they have done so often this season) found a way to open up a tight affair. After Curtis Langdon and Tom Pearson had rapped persuasively on the door but failed to beat it off its hinges, George Furbank played the locksmith, threading a delicious pass between four Saracens to a rampaging Burger Odendaal, collecting and scoring from 15m out.

The visitors thought they had replied equally delightfully, but a neat move at the front of a lineout was chalked off with Jamie George offside in the build-up. Two kickable penalties either side of the half-hour mark allowed Fin Smith to extend the hosts’ advantage.

Saracens were suddenly struggling for poise and precision in a penalty-ridden match. Both Farrell and Daly fumbled uncharacteristically to jeers of joy from a vocal home crowd, while Lucio Cinti ended up in touch trying to round Alex Mitchell. Smith’s boot was accurate on halftime to swell the lead to 10 points.

Having been beaten in the physical battle so far, Saracens turned to their burly bench, Mark McCall introducing four forwards at once as the clock struck 50. The brothers Vunipola were among those taking leave: Mako and Billy’s own storied Saracens careers were at an end unless their colleagues could find a route back.

Farrell showed them the way. There appeared little on as the fly-half zipped on to a pass, but a deft dummy opened a secret passage. Walls closing again, a delicate dribble to his left was judged perfectly, and Alex Lewington provided the grounding hand required in the corner. Daly converted from the touchline.

There was to be an intervention just as special and significant at the other end. Mitchell burst beyond the Saracens defence and appeared to be racing for the corner with only open pampas in front of him. He hadn’t accounted, however, for a pursuing Puma, Juan Martin Gonzalez somehow hauling the scrum-half into touch inches from the score that might well have sealed it.

Saints instead had to settle for a fourth strike from Smith’s boot, and the strength of their scrum earned them another. Was it to be enough? A Cinti scurry into the corner suggested not, but Northampton refused to let the nerves dictate. A Saracen was held up off his feet, soon joined in the air by the capacity home crowd as Ridley’s whistle blew. Down the M1 they will march in a bid to give Lawes a fitting final farewell.