Five months ago Mickelson had Tiger Woods as his playing partner at Pebble Beach and, while Woods crashed to a 75, he charged to victory from six behind.
At Castle Stuart this time the performance lifted the American star from the depths of 123rd - and in danger of missing the halfway cut - right into contention on seven under par.
And there was an element of relief about it a week before the Open Championship because it ended in brilliant fashion a run of eight successive over-par rounds, something that had never happened to him before.
After improving nine strokes on his opening round, Mickelson, who pitched in from 60 yards for an eagle two on his very first hole, said: "I'm really glad I added this tournament."
The left-hander was on holiday with his family in Italy when he decided to seek an invitation on Saturday and, luckily for him, there was one available.
"I just needed to play more - I've only played three tournaments the last couple of months.
"It's very helpful to see my game progress so quickly. I'm very lucky because I've got a very supportive family and when I was thinking about adding it after missing the cut last week (wife) Amy had the same idea simultaneously.
"It was very important (for his hopes next week) that I have a couple more rounds here.
"It will give a chance now on the weekend to have a couple more days of working on it.
"Hopefully it will get a little bit nastier because it's supposed to be some tough weather conditions next week."
Mickelson will not mind that because it was far from calm and sunny when he finished joint runner-up behind Darren Clarke at Sandwich last July - the best Open display of his long career.
He added: "This is a great place to play the Scottish Open. I thought it was instrumental last year in my finish in the British."
And that despite finishing only 58th.
He said: "I think the more I play the better it gets. It's not to the level that I would like yet, but I get closer each day."