Maxwell had just taken a catch when he went to field a ball hit into the deep by Phil Salt. With the dew settling on the Lord's outfield he slipped and was off balance as he threw and landed awkwardly. As he did so the 33-year-old clutched his back and looked in pain.
Maxwell went off, being replaced by a substitute fielder, but after treatment was able to return as Spirit won by 52 runs.
Maxwell had earlier made 21 off 15 balls in a partnership of 42 off 30 balls with England Test batter Zak Crawley (41 off 34) that set Spirit up for a match-wining 6-160 off their 100 balls.
Former England white-ball skipper Eoin Morgan scored 37 off 26 before West Indies' Kieron Pollard lashed an unbeaten 34 off 11 balls.
Aussie all-rounder Sean Abbott had begun well picking up the wicket of Adam Rossington second ball, but went for 28 off his 15 overall.
Originals were rarely in the hunt and were dismissed for 108.
They made a bad start when England's current white-ball captain Jos Buttler was dismissed for six and it didn't get much better. Salt made 36 off 34 but saw wickets tumble around him with Jordan Thompson taking 4-21 in 20.
Abbott made ten off seven, one of only three Originals players who reached double figures.
Nathan Ellis did not get a wicket but very bowled tightly, conceding 16 off 20 balls. During his third set the dangerous Andre Russell was run out as Originals tried to break the stranglehold.
Spirit's win enabled Trevor Bayliss to win the battle of Aussie coaches with Simon Katich leading the visitors.
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