Murphy also linked well with winger Shane Horgan, who crossed for the Lions' second try, and Denis Hickie, who was a menacing threat on the counter-attack.
McGeechan, the Lions coach, said: "It's what you want, players playing well and challenging so the next team up knows it has got to perform.
"When every group of players goes on the field and is challenged, that is what makes a successful Lions group.
"I thought the back three had a good game and it came from the control we had in the half-backs.
"It will have given them a lot of confidence. Geordan saw the chances well and that is what you want from back three players."
John Hayes did not enjoy such an outstanding evening and was replaced in the second half by Welshman Gethin Jenkins.
The performance of the tight five will be a cause for concern and it was not until Jenkins was introduced at tight-head and Taranaki began to run out of steam that the pack gained the upper hand.
In the first half they were wheeled at the scrum, shunted off their own ball, struggled in the line-out and were second best at the breakdown.
"The Taranaki pack played well, put us under a lot of pressure in the first half and I was happy with the way we responded," said McGeechan.
"The pleasing thing for me is that we are not just learning in training but on the pitch is well. That was a tough game up front.
"I thought our defence was outstanding. The fact there were no penalties in the second half shows a composure you can build things on. The fact we scored a try out of defence is very important. It shows we can turn one into the other."