England probably knew five of their top seven players for the T20 World Cup in Bangladesh in late September.
Danni Wyatt, Alice Capsey, and Nat Sciver-Brunt will join Knight and Amy Jones for this series.
Sophia Dunkley, Tammy Beaumont, and Maia Bouchier are competing for the second opener role, but all fell in tame fashion.
Dunkley scored twice by chipping to mid-wicket, Beaumont was bowled after being trapped in the crease, and Bouchier played an unattractive reverse sweep to cover.
There is uncertainty about all three players. Dunkley has only averaged 17 in her past 13 T20 innings, Beaumont has returned to the side after a two-year absence, and Bouchier has moved up and down the order and has yet to settle into a role.
There are still doubts about who should fulfil the finisher role at number seven. Dani Gibson (14) and Bess Heath (2) have both failed to seize their latest opportunity.
Charlie Dean (16 off 14 balls) and Sarah Glenn (13 not out off six) offered resistance and valuable runs alongside Knight, who played beautifully after a slow start, taking advantage of all the width and loose balls on offer as England added 69 runs off the last six overs.