Not bad for "a couple of old guys".
And the veterans - combined age 69 - did not disappoint with Britain's two-time Olympic champion coming out on top 6-3, 7-5 in an hour and 50 minutes.
Nadal, who has been out since August's Washington Open with a chronic foot injury, was clearly the more rusty of the two with Murray coming off a straight-sets win over compatriot Dan Evans on Thursday.
The Spaniard earned a break point in the third game of the match, but Murray saved it before breaking to lead 4-2 and serving out the set comfortably.
Nadal saved two break points at the start of the second set, and two more in the fifth game as the Beijing 2008 singles gold medallist showed his trademark competitive instinct.
After a couple of wonderful forehand winners from the 13-time French Open champion, with Spain's former monarch King Juan Carlos I in the crowd, Murray had to save a break point of his own before making it 4-4.
And it was the Scot who converted the second of two break opportunities to lead 6-5 before serving out to take victory.
Murray won their last meeting in the semi-finals of the Madrid Masters back in May 2016, but Nadal has won 17 out of their 24 competitive encounters.
He faces Russia's Andrey Rublev in Saturday's final after the world number five defeated Denis Shapovalov 7-6 (5), 3-6. 6-4.
The players are warming up for next month's Australia Open with Novak Djokovic, whose vaccine status remains unknown, set to bid for a fourth consecutive title and his 10th in total.
Were the Serb to win again, he would move to 21 career Grand Slams, one clear of Nadal and Roger Federer, who misses Melbourne as he recovers from knee surgery.
Murray has not played at the Australian Open since 2019 when he admitted he may not be able to play again due to a chronic hip condition.
But extensive surgery saw him return to the tour, and he won the European Open in October 2019.
A thigh injury ended his bid for a third consecutive Olympic gold at Tokyo 2020.