The champions are gone; the league leaders march on. It was a choke tackle at the end that finally finished Saracens off, initiated by none other than Courtney Lawes, playing his final match at Franklin’s Gardens. With it Northampton thwarted a last-gasp comeback by one of the country’s champion teams, so many of whom were also playing their last match.

So the English game says farewell, for now at least, to some of its most decorated players. Owen Farrell heads off to France without that last gong, so too the Vunipola brothers. Mark McCall revealed afterwards that ­Farrell had injured his quad on ­Monday and was a doubt for this right up to the warmup. Elliot Daly took on the ­kicking duties.

And yet it was two interventions of the highest class by Farrell that earned the visitors two second-half tries, the second by Lucio Cinti with just the one minute on the clock. But Saracens’ hunt for the kick of any kind that would have snatched an outrageous win even by their standards was snuffed out by the home defence.

Related: ‘It’s perfect’: Sale’s Ben Curry feeds on underdog status before spicy playoff

“I’m all right,” said Farrell. “It’s sad that this season is done and is done for a few of us here. I’ll look back at it fondly. It doesn’t feel special, but I’m sure it was [special to watch].”

The Saints defence, though, was unyielding, subjected to all Saracens could throw at it. Defeat here would have been too much for Northampton, having lit up this season so richly and progressed so far in Europe. They are no doubt still dogged by memories of their previous semi-final this season, against Leinster in Dublin, when they took so long to find their feet. This time, happily, they were on familiar territory for the visit of another pedigree team in a semi-final.

Sure enough, Saracens tore into them for most of the first 20 minutes. No doubt chastened by their own mystery non-appearance – the home defeat to Sale in the final round of the regular season that meant they had to come here in the first place – the visitors looked in the mood.

Plenty of teams – one thinks of Harlequins at the Tottenham Stadium in March – might have capitulated, but Saints managed to restrict them to just the two penalties in that period, both kicked by Daly.

More encouragingly still for Northampton, they were the first to cross the whitewash, at nearly the first time of asking. It might have been their only try of the match, but it was sharp and precise.

Cinti kicked loosely to Alex Mitchell, and the Saints were away on the counter. George Furbank made a half-break, and the full-back’s fabulous off-load sent Burger Odendaal to the line for the game’s first try.

Saracens thought they had scored their first try, five minutes after Northampton’s, when Jamie George was worked over from a short lineout, but it was ruled out by the TMO. George was in front of Ivan van Zyl as the latter chipped ahead.

The game was fast and brutal, nip and tuck, but Saints pulled further away on the approach to half-time, as Saracens started to lose their breakdown mojo. They conceded three penalties, each one slotted impressively by Fin Smith for a 10-point lead to Northampton at the break.

Saracens responded by introducing four substitutes 10 minutes into the second half. The pace of their game increased, and they soon had their first try. After some sharp phases working left, Farrell dummied, broke and chipped in the blink of an eye. And what a chip. The ball sat up invitingly for Alex Lewington to finish.

The game was in the balance again, Saracens just the three behind. Ollie Sleightholme, Northampton’s winger, went on a crazy, skilful medley of hacks ahead, only two minutes later, but the ball just eluded him as it bobbled over the dead-ball line.

Smith missed his first kick on the hour, before some brilliance by Mitchell elicited even more from Juan Martín González. England’s scrum-half seemed to have worked himself clear with a brilliant reverse pass to Fraser Dingwall, who returned the ball to him for a seeming run-in. But, no, González, a put-upon flanker no less, managed to run him down with a brilliant cover tackle to keep Northampton out again.

But if Saracens had the favour of the referee at the breakdown, they most certainly did not at the scrum. Smith sent the resultant penalties to the corner, or, with 10 minutes remaining, through the posts. After another penalty a few minutes into the final quarter, that took Saints more than a score clear.

Saracens came again, of course. With one minute to go, Cinti was over. Farrell’s flat pass was the key. Daly took it and sent the Argentine over out wide. Daly’s conversion set up the finale, but Northampton’s defence finished the job.

“This will mean nothing if we don’t turn up next week,” said Lawes. “We should be expecting to win games like this. We have proved we can beat the best.”