Williamson's unbeaten 70 off 43 balls was his best innings in this season's IPL by a long mark but Bangalore, long out of the playoff picture, managed to overhaul Hyderabad's 175 for seven with four balls to spare.
India skipper Virat Kohli (16) and AB de Villiers (one) were unable to get Bangalore off to a flying start but Shimron Hetmyer filled the void by blasting 75 runs off 47 balls, including four boundaries and six sixes.
The left-handed batsman arrived in Bangalore with great expectations, and a heavy price tag, but it was only in his final innings that he was able to fulfil them.
"At the start it was tough for me, just getting used to the environment and getting used to the IPL itself," said the 22-year-old before he jetted off to join his team mates in the West Indies squad for the 50-overs World Cup.
"Just coming out today, I said 'let's have some fun'."
With their top batsman David Warner already back in Australia preparing for the World Cup, the Sunrisers will be relying on results going their way in Sunday's final couple of group matches to get into the playoffs.
The Delhi Capitals will definitely be involved in the playoffs and they ended the slim hopes of the Rajasthan Royals with a five-wicket win in Saturday's other match.
At three-wicket burst from paceman Ishant Sharma in the powerplay set the home side on the path to their ninth win of the season and Rishabh Pant secured the victory with 23 balls to spare after smashing his fifth six in his innings of 53 not out.
The table-topping Chennai Super Kings visit bottom side Kings XI Punjab, while the third-placed Mumbai Indians host the fifth placed Kolkata Knight Riders on Sunday in the final group matches.
(Reporting by Nick Mulvenney; editing by Sudipto Ganguly)
