The striker is the club's all-time record European scorer with seven goals, but admits that notching in Europe's elite tournament would top everything else.
Greek cracks Panathinaikos visit in third qualifying round action this evening, and Murphy has tagged the tie even more important than the Scottish Cup final meeting with Celtic back in May, 2011.
Despite the fact that English Premier side Wigan are understood to be keen on his services after finally raking in £9.5million from the sale of Charles N'Zogbia to Aston Villa, Murphy says all his focus is on Well's progression in Europe.
He is also confident that his side has the ability to earn a result that will give them a solid foundation to take to Athens next Wednesday for the return leg.
The 23-year-old said: "I have played in some big games before, like in the Uefa Cup against Nancy and, of course, the Scottish Cup final the season before last against Celtic, but this is the biggest of the lot.
"Motherwell have never had the chance to try and qualify for the Champions League before and the fact that we have the first leg at home is a massive plus in that regard.
"It is just a really exciting prospect and the fact that no-one gives us a chance and that we are massive underdogs suits us just fine.
"We know that it will be about delivering a performance that balances up the need to get a win with avoiding conceding a goal. That is the target and we have a belief in our dressing room we can achieve that."
Murphy added: "I am proud I have scored seven goals for Motherwell in Europe, but I would trade every one of them for a winner tonight."
The frontman enjoyed his best season for Well last term when he posted a career-high 13-goal tally and courted interest from Championship side Blackpool. As he homed in on the grapple with the Greeks, he revealed his relish at the prospect of testing himself against top level defensive talent like former Rangers and France star Jean-Alain Boumsong.
He said: "Panathinaikos are stacked full of top-quality players with loads of international talent and Boumsong has seen it and done it all.
"Hopefully I can give him all the trouble he can handle, but when you play against guys of that level, you have to believe in yourself.
"This is the club's biggest-ever European tie and we are determined to give the fans a night to remember."
Motherwell's hopes have been boosted further by the news that Panathinaikos top scorer from last term, Argentine hitman Sebastian Leto, is injured.
Well boss Stuart McCall is set to hand former Bradford star Simon Ramsden his competitive debut in central defence alongside Shaun Hutchinson, and Murphy has backed the new boy to help the Steelmen erect an impenetrable iron curtain.
Murphy has no doubt that the versatile defender's arrival has been crucial to countering the departure of former club captain Stephen Craigan into retirement and Tim Clancy to Hibernian.
He said: "Simon has done a full pre-season with us and fitted in really well. He is an experienced player and facing the Greeks will not faze him. I have no doubt that he and Shaun can form a good understanding.
"It is just a massive bonus for us that we have been able to land a player of Simon's calibre for free. We are a bit light in terms of experience and Simon has loads of it. In Europe I think that experience is a quality that is vital."
With midfield enforcer Stevie Jennings also having left this summer, it looks likely that Nicky Law will fill his place in centre midfield in tandem with new skipper Keith Lasley.
It seems likely that McCall will opt for a 4-4-2 formation and Murphy may find himself up top with Michael Higdon.
The Fir Park favourite has vowed Well will give everything and leave their supporters filled with pride.
Murphy said: "Like I said, we know that we are big underdogs here but if we can nick the first goal then it will be very interesting to see how the Greeks react to that. But, as a group of players, we are determined to do the club proud."
