Montferrand - 20 Leinster - 23:EUROPEAN CUP: As smash and grab away wins go, this came straight from the manual. Gerry Thornley reports.

Calmness personified for the first 50 minutes of almost exclusive defending, stealthily keeping in touch with Brian O'Meara's three-pointers from the occasional sorties upfield, Leinster then turned the game on its head by opportunistically converting the two chances that came their way, the second in the 80th minute.

Just like that. They celebrated long after most of the disgruntled home crowd of about 8,000 had slunk off in the dank, cold twilight air, acknowledging the band of Leinster supporters who had noisily congregated in one corner of the Parc des Sports Marcel Michelin.

For those first 50 minutes or so, at which point Montferrand led 17-9, the home side looked physically the stronger. But then, when push came to shove, Leinster were undoubtedly the stronger mentally. So, while it looked a mite ominous from the steepling heights of the stands - surely the biggest and most spacious 13,000-capacity ground in Europe - it transpired there was no sense of foreboding in the Leinster camp.

All week long, the mantra within the camp was "Northampton, "Northampton". This was in reference to the sleeves-rolled-up 14-8 win away to the then European champions two seasons. Basically, it reinforced the need for Leinster to hang tough for long stretches of the game without the ball, as was invariably going to be the case away to real French contenders who had amassed almost 1,000 points in 20 successive home wins in Europe.

So, for the first 50 minutes all Leinster did, pretty much, was tackle. Or as Matt Williams put it "tackle, tackle and tackle". You sensed it was going to be a long day at the fringes, particularly when Emmet Byrne began emerging as a leading tackler early on. He did a big job in the scrums too.

Everyone contributed mightily to the defensive effort. Though the line-out malfunctioned without Malcolm O'Kelly until Leinster simplified things after the break, Leo Cullen was immense around the pitch and Aidan McCullen ably filled O'Kelly's role as a fourth back-rower.

It was McCullen's leg-pumping rumble in contact up the right flank which had given Leinster their first real go forward ball after 48 minutes and signalled the shift in balance. It was McCullen's ensnaring of the Montferrand winger Jimmy Marlu on the left touchline which earned turnover ball for Denis Hickie to counterattack elusively and effectively end any notion of the French playing a get-out-of-hail card in the six minutes of injury time.

For all the brilliance of Leinster's continuity and the cutting edge which a golden crop of backs have given them in recent times, much of their success has been founded on the homework done on opposing teams and defensive preparation. Thiey realigned their defensive system to counter Montferrand's emphasis on width.

Leinster didn't overcommit to rucks and always kept their line in shape. The back row, en bloc, were excellent, and the defending around the fringes was top-class, all the more so given Keith Gleeson jarred his ankle getting on to the plane in Dublin on Friday, was treated during the flight and was only just passed fit on the morning of the game. He's not one for flinching though. And, though we don't always see it, once again Brian O'Driscoll's work-rate and defensive effort typified Leinster's collective zeal.

All the while, Brian O'Meara's goalkicking from the occasional raid on enemy territory somehow kept Leinster in touch. The half-time score of 12-9 was "a result"and at the interval Willie Anderson reminded the players it generally takes a half a game or so to rediscover the old rhythms after a break.

"Fair play to them, they stuck at it and they worked together and they never gave up," said Anderson. As O'Driscoll also revealed there was a sense that, despite all their possession and territory, save for a classical French maul Montferrand surprisingly didn't hurt Leinster all that much. If those were their best shots, then no need to panic.

Stay cool was the message, and they did, even when Montferrand took up where they left off and Marc Reynaud flicked on Gerald Merceron's skip pass for David Bory to score in the corner. At 17-9 and 46 minutes in, Leinster's prospects looked as dreary as the misty skies.

It was then that they began to play, and half an hour would prove enough. The thing about Leinster is that, more than any other Irish side and more than most sides in Europe, they can always contrive a try.

"I think we had two opportunities, max, and you gotta take them. Gotta take them. And in fairness they took them. Whenever we held onto the ball for more than three phases we either got a penalty or a scrum," said Anderson. Leinster began finding particular joy in the Montferrand midfield, Shane Horgan bursting through and finding O'Meara in support, who had the vision to pivot and throw out a long flat pass to put D'Arcy over in the corner.

Although Merceron landed his fifth penalty, and O'Meara was guilty of his only poorish miss of the game, the force was undeniably with Leinster. Montferrand were buckling, and David Quinlan came in to midfield with Horgan moving to the wing after D'Arcy's departure to continue punching midfield holes.

Cue another replacement, Nathan Spooner. Christian Warner had wearily taken the ball up and been penalised for not releasing, his edge blunted after a Trojan defensive effort. It needed a game breaking big play, and Spooner delivered on Williams' 75th minute gamble.

A maul on the left had been shunted back, O'Driscoll had barely reached the gain line before setting up quick ball, and with most of the traffic moving on to the right again, Spooner came from deep to return to the blind side. There was only Hickie with him but the outhalf's long flat pass - possibly a tad forward - gave the winger every opportunity to take Sebastien Bozzi and the mouthy, showy Richard Cockerill on the outside. That made it perfect, O'Meara's stunning touchline conversion giving them a three-point buffer.

One chance. Taken. And Leinster made off into the night.

Scoring sequence: 7 mins - Merceron pen 3-0; 11 mins - O'Meara pen 3-3; 17 mins - Merceron pen 6-3; 22 mins - O'Meara pen 6-6; 25 mins - Merceron pen 9-6; 32 mins - O'Meara pen 9-9; 35 mins - Merceron pen 12-9; 46 mins - Bory try 17-9; 55 mins - D'Arcy try, O'Meara con 17-16; 62 mins - Merceron pen 20-16; 80 mins - Hickie try, O'Meara con 20-23.

MONTFERRAND: S Viars; J Marlu, J Ngaumo, R Chanal, D Bory; G Merceron, G Sudre; S Bozzi, R Cockerill, L Tsabadze, T Jaques, O Brouzet, A Audebert, M Raynaud, O Magne. Replacements: D Von Hoesslin for Sudre (40 mins), J Machacek for Audebert (74 mins).

LEINSTER: G Dempsey; D Hickie, B O'Driscoll, S Horgan, G D'Arcy; C Warner, B O'Meara; R Corrigan (Capt), S Byrne, E Byrne, L Cullen, A McCullen, E Miller, V Costello, K Gleeson. Replacements: D Quinlan for D'Arcy (56 mins), N Spooner for Warner (75 mins), G Hickie for S Byrne (82 mins).

Referee: Paul Adams (Wales).