Just three points have separated the sides over the course of the two previous games and with the series on the line, this weekend's decider looks set to be equally tight.
"This is unique, it's very special, it's every four years with an elite group of people," said Phillips after being named as half back partner to Ireland's Jonny Sexton.
After missing the second Test altogether, Phillips is one of six changes in a side which features 10 Welshmen. He replaces Ben Youngs at nine with Conor Murray on the bench.
"I'm delighted to be back in the side. It was different watching from the stands last week - different kinds of emotions," said the Bayonne man.
"But I'm pleased to have been given the honour this week. I'm feeling really good now and hopefully I can go out there and perform.
"If we can achieve a series win on the weekend it would top everything."
Phillips' fellow Welshman Alun Wyn Jones leads the Lions tomorrow from the second row while there is an all Welsh centre partnership of Jamie Roberts and Jonathan Davies.
"He's a great guy," was Phillips' verdict on captain Jones.
"He's performed tremendously well on the tour as a player. He is a leader off the pitch and on it. He's captained Wales and the Ospreys a few times.
"He'll grow into the role and I'm very happy for him. He'll be leading from the front. He's aggressive but he's controlled. Hopefully we'll all back him up on the weekend and deliver a performance for him."
While tomorrow's match is one the Lions squad freely admit is a huge encounter, Warren Gatland's men know they will have to stay cool in the heat of battle to have a chance of success.
Echoing that opinion, Phillips added: "We have to concentrate on ourselves and do the basics well.
"Obviously deep down we know how big it is but you've got to distance yourself from all that and concentrate on your own role and what's got you here in the first place."