A horror of a penalty kick for Stephen Myler. 

He tries to kick it left, but it goes wildly right. Not one to remember.

Will Fraser penalised now for Saracens, as he tries to charge down a Ben Foden kick. 

Will the referee adjudge it to be foul play? YES. Yellow card for Fraser and penalty Saints.

Discipline in the opening 10 minutes has not been good for the hosts. 

Courtney Lawes, playing as blind-side flanker for Saints, goes striding forward with force.

Saracens concede a third penalty in eight minutes, as Duncan Taylor fails to roll away, and this time Saints go for the points. 

Stephen Myler lines it up to the right of the posts but it goes just wide. 

Image source, Getty Images

A beautiful burst from Owen Farrell sees Saracens go on the attack. 

Sarries win a penalty as Saints are penalised for coming in at the side. 

Farrell and his famous tilty head get the first points on the board after a long-range kick goes through the posts. 

Northampton's line-out is shoddy and Jackson Wray gathers for Saracens. 

A long kick up field is gathered by Saints and it's another penalty their way. And another line-out for the visitors in the Sarries 22.

A short one to the front doesn't work. Ooops. 

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First line-out to Saracens, and it's caught successfully by Maro Itoje.

Schalk Brits puts in some lovely foot work as Sarries push forward but Northampton win possession and then win a penalty, which is kicked to touch.  

Duncan Taylor, so impressive for Scotland in the Six Nations, is down injured already for Saracens, so play is stopped while he gets the once over from the physios. 

Owen Farrell boots us underway. Glorious weather in the capital. 

England pair Ben Foden and Brad Barritt lead out their respective teams at Allianz Park.

It's first in the Premiership v fifth in the Premiership. One will reach the Champions Cup semi finals. One will...erm...not.

Let's find out who Wasps will be up against. 

Ex-England international Brian Moore seemed to enjoy the first quarter-final...

Hopefully we can expect more of the same drama at Allianz Park.   

Here's how 2014 runners-up Saracens match up against 2000 winners Northampton in Europe. 

Image source, .

It was Saints who scuppered Sarries.

Image source, .

Northampton won four of their Pool Three games - beating Pro12 sides Glasgow and Scarlets - but failed to overcome Top 14 side Racing 92, who topped the group.

Saints have won six and of their last nine away matches in the competition. One of their three losses came in last season's quarters against Clermont. 

Image source, Getty Images

Sarries made it look easy in Pool One: played six, won six, four bonus points. Lovely job.

However, no club has won all their pool games and gone on to win the competition in the same season. Gulp.

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There's one other Premiership team competing for a semi-final place this weekend. 

Leicester face Stade Francais on Sunday afternoon. Welford Road is looking in good nick for the English-French battle.

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Wasps' match winner Jimmy Gopperth has been speaking to BBC Radio 5 live about his last-minute conversion which completed his side's stunning comeback against Exeter in the first of today's quarter-finals.

"As a goalkicker they are the moments you practice night and day," he said. "I had to treat it as my first kick of the match. As soon as I struck it, I knew it was good,. The win was a great team effort from that position and we showed a lot of character. I was happy to finish it off for the boys."

Luther Burrell returns for Saints, after the England centre missed last weekend's defeat by Wasps in the Premiership.   

But hooker Dylan Hartley is still out with concussion, while Lee Dickson, Kieran Brookes, Tom Wood, George North and Sam Dickinson are also absent for the visitors. 

Jamie Elliott comes in on the wing, while Courtney Lawes shifts from second row to blind-side flanker.  

Northampton: Ben Foden; Ken Pisi, George Pisi, Luther Burrell, Jamie Elliott; Stephen Myler, Kahn Fotuali'i; Alex Waller, Mikey Haywood, Paul Hill; James Craig, Christian Day; Courtney Lawes, Ben Nutley, Teimana Harrison

Replacements: Reece Marshall, Campese Ma'afu, Gareth Denman, Victor Matfield, Michael Paterson, Tom Kessell, JJ Hanrahan, Harry Mallinder

Image source, Google

Winger Chris Wyles and flanker Jackson Wray come in as Saracens make two changes to the side that won at Bath last week.

England trio Billy Vunipola, George Kruis and Maro Itoje all start. 

Saracens: Alex Goode; Chris Ashton, Duncan Taylor, Brad Barritt, Chris Wyles; Owen Farrell, Richard Wigglesworth; Mako Vunipola, Schalk Brits, Petrus Du Plessis; Maro Itoje, George Kruis; Jackson Wray, Will Fraser, Billy Vunipola

Replacements: Jared Saunders, Richard Barrington, Titi Lamositele, Alistair Hargreaves, Michael Rhodes, Neil De Kock, Marcelo Bosch, Ben Ransom

Image source, Getty Images

Exeter's hopes for a first ever European semi-final appearance are over, as Wasps reach the last four for the first time since 2006-07 season, when they went all the way to the title. 

They will now face either Saracens or Northampton in the semi-finals. Their battle for the final four starts at 17:45 BST. Stay with us here, as we'll be bringing you live updates from Allianz Park.

What an unbelievable finish at the Ricoh. 

Jimmy Gopperth's angled conversion from the right-hand side bisected the posts and completed Wasps' stunning comeback. 

The New Zealander told BT Sport: "I was so happy to have an opportunity to have a strike. You have to nail those moments. I don't think I've ever celebrated a kick like that."

Some of his team-mates couldn't even watch him take it!

Jeremy Guscott
Former England international on 5 live Sports Extra

"Knockout rugby at its very best - the last kick in the last minute of this amazing quarter-final. We've seen brilliant rugby from both sides - there didn't deserve to be a loser today."