Chasing 116 to win from 14 overs, Englishman Alex Hales made an unbeaten 63 as the Thunder won with 11 balls to spare.
Hales' 39-ball knock featured four sixes - he's hit 30 this tournament, eclipsing Marcus Stoinis' previous record of 28 for the most sixes in a KFC BBL edition.
The Thunder also banked the bonus point in their Adelaide Oval triumph to rise to third on the ladder and seal a berth in playoffs, starting on Friday.
Hales reached his half-century from just 31 balls and combined with captain Callum Ferguson (46 not out) for a match-winning partnership.
Thunder opener Usman Khawaja was bowled for a golden duck by Daniel Worrall on the first ball of the innings.
Jake Weatherald played a lone hand in the Strikers's 4/115, carrying his bat through the reduced innings.
The left-hander cracked eight fours and four sixes and dominated his side's scoring.
At the seven-over midway point, Weatherald had scored 29 of Adelaide's 3/37 after the dismissals of Alex Carey (two), Phil Salt (one) and Travis Head (two).
It took until the 11th over - the sole Power Surge over in the restricted match - for another batsman to reach the boundary, when Jon Wells struck consecutive fours.
Weatherald repeated that feat in the same Milne over, reaching his half-century from 36 balls.
Wells (21 from 18 balls) fell in the 13th over, ending a 63-run partnership with Weatherald, who continued a late flourish.
Adelaide slips to fourth spot and are relying on the results of the last three regular-season games on Tuesday falling their way. The finals door is open for Hobart Hurricanes (fifth), Brisbane Heat (sixth) and Melbourne Stars (seventh).
The highest Adelaide can now finish is fourth position, but that will depend on the Hurricanes, Heat and Stars not picking up maximum points in their matches.
Hope still remains for the Strikers pending Tuesday's final day of the regular season.