Where they finished
Topped the league stage, and became IPL champions for a third time in five years. No team has as many as titles as they do.
A highly productive middle order. Their batsmen from Nos. 3 to 7 made 10 fifty-plus scores and only three of them were in vain. Kieron Pollard produced one after Samuel Badree took a hat-trick and reduced Mumbai to 7 for 4 in a chase of 143. Nitish Rana made 62 not out without hitting a single four, but his seven sixes made sure Mumbai recorded their highest chase of 199 with 4.3 overs to spare. Krunal Pandya, returning from a groin injury, made successive forties in successive knockout games. He was the Man of the Match in the final and gave his team the belief that their line-up was deep enough to overcome any crisis.
A phenomenal bowling unit. Jasprit Bumrah won a Super Over for his team with a medley of big dipping slower balls, a trick from Dwayne Bravo's bag to down his own team. A few weeks later, with everything on the line, he took out one of the best chasers in the business - and his mentor - MS Dhoni to fortify Mumbai's defence of 129. No one bowled as many as his 164 balls in the death. He was also among the top-five wicket-takers of the season.
Bench strength, perhaps the most decisive factor in their triumph. Legspinner Karn Sharma, having been surplus to requirements for much of the group stages, vaulted Mumbai into the summit clash with his best IPL figures of 4 for 16. Ambati Rayudu went over a month without cricket before he was drafted back in the XI and hit a match-winning half-century. He was one of six changes to the XI, which defended 24 runs off the last 18 balls to slap Kolkata Knight Riders with their first loss in 13 chases at Eden Gardens.
Rohit Sharma spent half of Sunday night grimacing at the way his team bled wickets. Then his bowlers intervened and he could have, if he wanted to, slept hugging the IPL trophy. So at this point he wouldn't really care that he made 333 runs at an average of 23.78 and a strike-rate of 121.97. But, for the record, the uncapped Rana, despite playing four fewer innings, matched that run tally. The Mumbai captain looked rather unsure of himself early in the campaign, and especially against legspin. He struggled to pick the googlies of four different bowlers - Badree, Imran Tahir, Rashid Khan and Amit Mishra - and it was only when he came up against a team that did not have a legspinner that he made his first double-digit score of the season. Perhaps coming back from a lengthy injury lay-off - he had played only two List A matches since October 2016 - played some part in Rohit's productivity going down.
Lasith Malinga and his rip-roaring yorkers are not quite extinct yet. At 33, having spent much of the last year recuperating from a chronic knee injury, he still had the goods to harass Steven Smith, one of the best batsmen of this generation, his leg stump, and his poor defenceless boots. But performances like that, which in times past were blasé, are starting to become more precious. Malinga conceded 50 runs or more in two successive matches. Heck, he was hit for 50 runs by one single batsman - Hashim Amla when he made 104 not out. Times, they are a-changing. Legends, they may be fading.
Their strange aversion to Rising Pune Supergiant. Three losses in the league games, one even when they were chasing at their beloved Wankhede, did indicate some mental scarring. But, when there was a trophy to steal, they rose above.
The missing ingredient
Space in their trophy cabinet.
Out of control
Their party sure will be.
Alagappan Muthu is a sub-editor at ESPNcricinfo