* Farrell, Murray send strong message
* Defence key to victory
* Crusaders dominated scrum but heavily penalised (Adds details, quotes)
WELLINGTON, June 10 (Reuters) - Flyhalf Owen Farrell slotted four penalties as the British and Irish Lions produced a performance of test match intensity to beat the Canterbury Crusaders 12-3 in Christchurch to win for the second time on their New Zealand tour on Saturday.
Warren Gatland's Lions had been under immense pressure after a mediocre start to their 10-match tour, with an unconvincing 13-7 victory over the Provincial Barbarians and a 22-16 loss to the Auckland Blues on Wednesday.
But a victory born of a huge defensive effort and the almost unerring boot of Farrell - the one kick he missed looked from TV pictures to have gone over - will give them a major boost as they head to Dunedin to face the Otago Highlanders on Tuesday.
"We can be pleased with our defence, we probably need to be more clinical when we do get linebreaks but we are happy with our turnaround tonight," Lions captain Alun Wyn Jones said.
"We tried to improve from the last game ... I wouldn't say that we were off track, I'd say we are just keeping our momentum going."
Richie Mo'unga kicked a first half penalty for the only points for the Crusaders, who have claimed seven Super Rugby titles and won all 14 of their games in the competition this season.
"We didn't have our rhythm," Crusaders captain and All Blacks second row Sam Whitelock said.
"Full credit to them they put pressure on us and our mistakes kept them in the game."
Scrumhalf Conor Murray and Farrell both sent strong messages that they should be the starting Lions halfback combination for the first test in Auckland on June 24 with their attacking kicking game putting immense pressure on the Crusaders.
The tourists also upped their intensity on defence, shutting down the Crusaders attacking options with their fast line speed and forcing them into mistakes.
The Lions, however, suffered two injuries with fullback Stuart Hogg receiving a bad cut above his left eye when he accidentally collided with Murray's elbow while chasing a high kick.
Centre Jonathan Davies, making his first appearance on the tour, also failed a head injury assessment when he was tackled heavily by Mo'unga in the first half.
The battle between the packs had been seen as crucial with the Crusaders having six All Blacks forwards in their starting side, including the likely starting test front row.
French referee Mathieu Raynal, however, did not allow any momentum to develop and caused a great deal of confusion with some of his decisions.
The first four scrums ended in penalties against the home side, with the first completed scrum not until the 21st minute when the Crusaders drove over the top of the Lions and caused an all-in shoving match.
Raynal's enigmatic decision-making was evident when he penalised Crusaders loosehead prop Joe Moody during an attacking scrum when he had Tadhg Furlong under extreme pressure.
The Lions had a 9-3 lead at halftime and Farrell appeared to have slotted his fourth penalty in the 45th minute but the assistant referees did not raise their flags as the ball soared high above one upright.
Farrell did add his fourth penalty with 10 minutes remaining in the game and then finished off a clinical performance when he punted the ball after the fulltime hooter. (Reporting by Greg Stutchbury in Wellington; Editing by Nick Mulvenney)