Harlequins will travel to the Leicester Tigers in the Aviva Premiership semi-finals after beating Northampton Saints 22-19 at the Stoop on Saturday.

The defending champions turned on the style with right wing Tom Williams, hooker Rob Buchanan and centre Tom Casson scoring tries with fly-half Nick Evans landing two conversions and a penalty.

Saints, narrowly denied after rallying from 22-5 down, replied with tries from left wing Jamie Elliott, hooker Dylan Hartley and lock Christian Day, on his 100th appearance for the club. Fly-half Stephen Myler converted two of the tries but had earlier missed two penalties and a conversion.

Harlequins leapfrogged Northampton to finish third on a day when the two sides, already assured of their play-off places before the final day of the regular season, served up a feast of attacking rugby.

Evans kicked Harlequins into an 11th-minute lead with a simple 20-metre penalty after Saints strayed offside in front of their own posts. Quins increased their lead 11 minutes later when a finely judged kick down the right touchline by Danny Care bounced perfectly for Williams - and cruelly for Northampton full-back Ben Foden - leaving the winger with a clear sprint to the line for a try converted by Evans.

The visitors responded with a sweeping attack which resulted in centre Luther Burrell timing his pass to perfection to send right wing Ken Pisi through a gap in the home defence. But referee Tim Wigglesworth consulted television match official David Grashoff before the try was ruled out because a would-be Harlequins tackler had been obstructed in the build-up.

Northampton were not denied for long as Foden bounced back from his earlier misfortune to provide a kick behind the Quins' defence which enabled Elliott to collect and race clear for the line. Myler's conversion from the left touchline drifted wide.

The fast-moving game continued to swing from end to end and Mike Brown's 40-metre kick down the middle from his own half had alarm bells ringing for the Saints. But Elliott cleared the danger, reacting quickly to reach the loose ball just ahead of the Harlequins fullback.

Foden's fluctuating fortunes took a turn for the worse when Evans read his pass perfectly to grab an interception but, as he kicked ahead down the line, the fly-half was crash-tackled into touch by the covering Courtney Lawes before he could begin the chase.

Quins scored their second try less than two minutes into the second half when flanker Luke Wallace flicked up a pass as he was tackled for Buchanan to charge through and ground the ball on the foot of the post. Referee Wigglesworth once again referred to the TMO before allowing the try, converted by Evans.

The fly-half had a chance to increase his side's 17-5 lead three minutes later but put his long-range penalty wide.Quins struck again in the 51st minute following a tremendous break through the middle by Care. He was stopped just short but number eight Nick Easter moved the ball on before George Lowe supplied the final pass for his centre partner Casson to touch down.

Northampton launched a fightback which produced 14 points in a seven minute spell. A superbly executed rolling maul enabled Hartley to celebrate his British and Irish Lions selection with a try before a great passing move along the line ended with Day crossing for their third try. Myler converted both to set up a grandstand finish but Quins held on to their slender lead.

Harlequins boss Conor O'Shea is relishing the prospect of his side's trip to Leicester for the their semi-final clash. They have already beaten the Tigers 22-9 at Welford Road and 25-22 at the Stoop this season, but director of rugby O'Shea said: "That's kind of irrelevant.

"The next game is always the big game so we need to turn up with the mindset we had today, the intensity and the intent we had today, but we have to do it for 80 minutes. If you go to Welford Road and you don't do it for 80, it's not good enough. We are ready for the incredibly exciting test next week. If we can take our chances we'll be right in it."

England captain Chris Robshaw, not chosen this week for the British and Irish Lions tour to Australia, faces a battle to recover from a twisted ankle in time for the semi-final after missing today's win. O'Shea said: "We'll know the minute he starts running on Monday or Tuesday. He's desperate to play and get back out there after the disappointment he suffered this week. Selection is subjective, but we feel he should have been there. But, if he doesn't quite make it, I thought Luke Wallace was magnificent today."

Northampton face Saracens in the final four with director of rugby Jim Mallinder wary of their artificial playing surface. "It's an unknown for us being away to Sarries in terms of the new pitch there," he said. "But we're not going to go there worried about them. We know they are a quality side, very difficult to beat, but we also know that, on our day, we've got a real good team.

"If we can put our play together for 80 minutes then we can upset the favourites. We are very motivated. We have players leaving the club, but we have been away to various grounds and to various sides this year as underdogs and we have turned them over."

Northampton's Ken Pisi is tackled by the Quins defence © Getty Images

Enlarge