The winger found the net inside 20 seconds of the second half at Stadium: MK with a deflected strike.
It doubled the Lionesses’ advantage, with Georgia Stanway’s penalty on 40 minutes all Sarina Wiegman’s side had to show for a dominant first half in which Manchester United forward Alessia Russo also hit the woodwork.
Kelly, England’s Euro 2022 final hero last summer, travelled to the latest international break on the back of three goals in her last four matches for City.
And she could well have added to that tally earlier than she did in Milton Keynes when she miscued an effort with the outside of her boot after working the space well inside the area.
The City winger was joined in the starting XI by Alex Greenwood, who would provide an assist for England’s third when her near-post cross from the left was fired home by Russo.
Lauren Hemp and Laura Coombs – making her first international appearance in eight years – were introduced after the hour as the hosts continued to turn the screw.
And number four would follow with 12 to play when Lauren James, who converted Lucy Bronze’s layoff to rubber stamp the victory.
The Lionesses’ defence of the Arnold Clark cup continues when they face Italy on Sunday 19 February, who were beaten by Belgium in the opening match of this year’s tournament.
Elsewhere, Filippa Angeldahl helped Sweden to a convincing 4-1 friendly win over China.
The midfielder played over 60 minutes for the 2020 Olympic silver medallists, who were three goals ahead inside 15 minutes thanks to Johanna Rytting Kaneryd early strike and a brace from Madelen Janogy.
China pulled one back early in the second half through Yuyi Xiao, but Everton’s Nathalie Bjorn added a fourth with 25 to play to complete the scoring.
Next up for Sweden is another friendly against Germany on Tuesday 21 February, with kick-off scheduled for 17:15 (UK).
There was less good news for Yui Hasegawa though, who couldn’t prevent Japan from a 1-0 defeat to Brazil in their SheBelieves Cup opener.
The midfielder played just over 60 minutes in Orlando, but Debinha’s late strike would prove the difference.
Hasegawa and co. are back in action on Sunday 19 February when they face hosts the United States at 20:30 (UK).
