The Englishman's thunderous knock, punctuated with six sixes and as many fours, helped Delhi overhaul Mumbai's total of 194 with seven wickets in hand.
After losing to Kings XI Punjab and Rajasthan Royals in the first two games, England opener Jason Roy led Delhi's charge with an unbeaten 53-ball 91 and he was ably supported by Rishabh Pant, who smashed a 25-ball 47.
Stanlake scored the winning runs from the No 11 berth on Thursday as Sunrisers squeaked to a one-wicket win over Mumbai Indians, but was not required this time around as Williamson (50) and Shakib (27) put on 59 for the fourth wicket, their dismissals coming too late for Kolkata.
Gautam Gambhir has seen Suryakumar Yadav flourish under him at Kolkata Knight Riders, but now representing different franchises, Gambhir saw his former teammate promoted to open the innings and score a 32-ball 53 that set the tone for the Mumbai Indians.
He may have started his maiden appearance at the top of the batting order in Twenty20s with a memorably fifty at his home ground, but Suryakumar Yadav wasn't thrilled with his effort. We knew that if we take it to the last over, we were going to win the game. Iyer failed to score off the last two balls of the 19 over, but said that he and Roy were confident of scoring the necessary 11 runs in the final over. I said I didn't mind batting anywhere as I am flexible.
After all, Mumbai Indians lost its third successive match of the Indian Premier League's eleventh edition.
Mumbai have had an even worse start than Delhi, having lost all 3 of their matches to Chennai, Sunrisers and now, Delhi. A quick single and the job would have been done, but Mustafizur did not allow one of the most successful strikers of the day to connect the next three balls. "We're a risky side if we keep going like that", he added. Chris Lynn did look unsafe scoring 49 runs (including 1 six and 7 fours) off just 34 balls, but apart from him no one could weave any magic. They batted really well and did not give us a chance in first 10-12 overs.
In between those two deliveries, Roy compiled an innings of relentless, clean hitting that took Daredevils to their first win of the season.
Speaking about the tense finish Iyer said "As a batsman, you would love to close down the chase at the earliest, but they bowled some really good slower balls and the last over, it was tougher for Jason to pick up". We wanted just one wicket.