Mumbai had to defend a lowly 129 for eight and managed it in world-class fashion.
Dan Christian had to hammer a boundary off the final ball to score the winning runs, but could only muster two and an exhilarated Mumbai celebrated ecstatically.
A stunned Pune – in control for 80 % of the match – was left stranded on 128 for six.
The crucial moment of the match came in the final over when Pune needed 11 runs off six balls off Johnson to clinch it.