Tries from James Lowe, Rhys Ruddock, Andrew Porter, Cian Healy, Ross Byrne, Luke McGrath and Ed Byrne saw the away side ease past the current Premiership leaders.
Leinster had the perfect start to the game with Lowe going over for the opening try of the game after just two minutes following a break by Jordan Larmour, who left him with the easy task of placing the ball over the line. Captain Johnny Sexton slotted over the conversion to make it 7-0 early on.
However, the hosts hit back almost immediately through Ashee Tuala, who was fed by Dan Biggar on the wing and he dived over the try-line. Biggar made it honours even with the kick with only six minutes on the clock.
Things got better for Biggar and the Saints minutes later as he knocked over a penalty to give the home side a three-point lead.
Although the topsy turvy game continued with the men in blue notching up their second try just before the quarter hour mark with some nice work from Jamison Gibson-Park leaving him just short of the line. Leinster recycled the ball well and Ruddock powered over from close range. Again Sexton kicked the extras to make it 14-10.
Over the next 10 minutes Northampton went ahead once again thanks to the boot of Biggar as he kicked another two penalties.
The Saints couldn’t hold on to the lead going into half-time however as Porter slipped over following sustained pressure from the away side in the Northampton 22. Sexton couldn’t add the extras this time around, but it was 19-16 to Leinster come the half-time whistle.
Leinster began the second-half just like they did the first going over for an early try through Healy after some brilliant work from the pack. The downside for the team was that Sexton was injured just before the score, but his replacement Byrne made no mistake with the conversion to stretch the lead.
Five minutes later and Byrne was in for a try of his own as Caelan Doris burst through the opposition defence before passing to the playmaker to touchdown. Byrne missed the conversion but things got worse for Saints as Alex Waller was sent to sin-bin.
Garry Ringrose followed him to the bin a couple of minutes later for a poor tackle on Biggar.
Northampton went in search of a score to get themselves back into the game, but error after error meant they failed to add to the scoreboard.
Leinster were ruthless in attack on the other hand and when they broke into the Northampton half they made no mistake once they got close to the try-line as substitute McGrath barrelling over from right in front of the line. Byrne couldn’t kick the conversion from the touchline but it was a sixth try of the game for the four time champions with less than five minutes left.
Last season’s runners-up weren’t finished yet with replacement front-row Ed Byrne charging over as the clock struck red to make it a seventh try of the afternoon for Leinster. Ross Byrne converted with the last kick of the game to make 43-16 come full-time.
The win leaves Leinster at the top of Pool 1 and means they have won all 10 of their opening games of this season, while Northampton now face a tough challenge to get out to the knock-out stages.
To make matters worse for the Saints is that they must head away to Leinster for the reverse fixture this day next week and will be hoping for a much improved performance to try and get one over on the Irish province, but Leinster look on course early on to add a record fifth title to their name come the end of the season.
Ulster name team for Northampton Quarter-Final trip
Michael Lowry is named to start at full-back, and is joined in the back three by Jacob Stockdale and Robert Baloucoune. Stuart McCloskey and James Hume will form the midfield duo, and Billy Burns and John Cooney are the starting half-backs.
In the front row, Eric O’Sullivan, Rob Herring and Marty Moore retain their starting berths. Alan O’Connor will partner Kieran Treadwell in the second row. Last week’s Player of the Match, Sean Reidy, will start at blindside flanker, with Jordi Murphy skippering the team at openside and Nick Timoney at Number Eight.
John Andrew, Andrew Warwick, Tom O’Toole, Matty Rea and Greg Jones will provide the forward reinforcements from the bench, with Alby Mathewson, Ian Madigan and Ethan McIlroy named as the back line options.
Ulster team to play Northampton Saints, Challenge Cup Quarter-Final, Saturday 10 April at Franklin’s Gardens (kick-off 8pm, live on BT Sport):
(15-9) Michael Lowry, Robert Baloucoune, James Hume, Stuart McCloskey, Jacob Stockdale, Billy Burns, John Cooney;
(1-8) Eric O’Sullivan, Rob Herring, Marty Moore, Alan O’Connor, Kieran Treadwell, Sean Reidy, Jordi Murphy (Capt.), Nick Timoney.
Replacements: John Andrew, Andrew Warwick, Tom O’Toole, Matty Rea, Greg Jones, Alby Mathewson, Ian Madigan, Ethan McIlroy.
Big names miss out for Ulster
The back line sees just one change from the side that played Toulouse last Friday. Michael Lowry, Jacob Stockdale and Matt Faddes all retain their positions in the back three. Stuart McCloskey and James Hume are the starting midfield duo. Billy Burns returns at fly-half and will captain the side; he will partner John Cooney at scrum-half.
The front row remains unchanged for this game. Rob Herring is named at hooker, with Eric O’Sullivan and Marty Moore packing down at loosehead and tighthead prop. Alan O’Connor will partner with his brother David – who will make his first Heineken Champions Cup start with Sam Carter missing out through concussion. Sean Reidy has been selected at blindside, with Jordi Murphy returning at openside. Nick Timoney comes in to start at Number Eight to replace the injured Marcel Coetzee.
John Andrew, Kyle McCall, Tom O’Toole, Matty Rea, and Greg Jones are the forward bench options. Academy player, Ethan McIlroy could make his European debut if called upon from the bench, and is named alongside Alby Mathewson and Ian Madigan in the back line replacements.
Ulster team to play Gloucester, Heineken Champions Cup Round 2, Saturday 19 December 2020 at Kingsholm Stadium, kick-off 3.15pm, live on BT Sport / beIN Sport:
(15-9) Michael Lowry, Matt Faddes, James Hume, Stuart McCloskey, Jacob Stockdale, Billy Burns (Capt.), John Cooney;
(1-8) Eric O’Sullivan, Rob Herring, Marty Moore, Alan O’Connor, David O’Connor, Sean Reidy, Jordi Murphy, Nick Timoney.
Replacements: John Andrew, Kyle McCall, Tom O’Toole, Matty Rea, Greg Jones, Alby Mathewson, Ian Madigan, Ethan McIlroy.
Ulster name strong side to face Toulouse
In the back three, Jacob Stockdale returns from international duty to the left wing, joining Michael Lowry at full-back and Matt Faddes on the right wing. In midfield, Stuart McCloskey also returns from the Ireland squad to partner with James Hume. Ian Madigan has been named at fly-half alongside John Cooney at scrum-half.
Having made his international debut against Scotland last week, Eric O’Sullivan, comes in to take the starting berth at loosehead prop. Rob Herring also returns from Ireland duties and is named at hooker, with Marty Moore retaining his position at tighthead. Alan O’Connor will partner with Sam Carter, who will lead the side from the second row. Sean Reidy and Jordi Murphy are named at blindside and openside, with Marcell Coetzee completing the pack at Number Eight.
John Andrew, Andrew Warwick, Tom O’Toole, David O’Connor, and Matty Rea provide the forward options, with Alby Mathewson, Stewart Moore and Craig Gilroy offering back line cover from the bench.
Ulster team to play Toulouse, Heineken Champions Cup Round 1, Friday 11 December 2020 at Kingspan Stadium, kick-off 8pm, live on BT Sport / beIN Sport:
(15-9) Michael Lowry, Matt Faddes, James Hume, Stuart McCloskey, Jacob Stockdale, Ian Madigan, John Cooney;
(1-8) Eric O’Sullivan, Rob Herring, Marty Moore, Alan O’Connor, Sam Carter (Capt.), Sean Reidy, Jordi Murphy, Marcell Coetzee.
Replacements: John Andrew, Andrew Warwick, Tom O’Toole, David O’Connor, Matty Rea, Alby Mathewson, Stewart Moore, Craig Gilroy.