Taylor Charters continued his winning run with loan club Gateshead - but Tristan Abrahams made a losing start with Grimsby.
Their fellow Carlisle United loan man Lewis Bell, meanwhile, was an unused sub in his first game with Warrington Town.
Midfielder Charters got his third start for Gateshead in National League North.
And the league leaders were too good for Leamington as they won 3-1.
Charters played the first 59 minutes before being replaced by ex-Blues striker Cedwyn Scott.
Macaulay Langstaff's double after Paul Blackett's opener earned a third straight win for Heed since Charters joined on a month's loan.
Striker Abrahams, meanwhile, went straight into the Grimsby side for their National League clash with Bromley.
Frustrating one to take today, Opportunity to put it right Tuesday. Fans were class from start to finish👏🏾
— Tristan Abrahams (@TAbrahams_) January 22, 2022
He played 79 minutes before being replaced in the 2-1 Blundell Park defeat.
Jordan Maguire-Drew put the Mariners ahead before a Bromley side featuring ex-Blues defender Byron Webster turned things around with goals from George Alexander and Jude Arthurs in front of a 5,854 crowd.
Teenage winger Bell was on the bench for Warrington after joining them on loan.
The Northern Premier League Premier Division side's boss Mark Beesley, though, did not turn to the United prospect as they went down 2-1 at home to a South Shields team managed by Sunderland legend Kevin Phillips, and one of whose goals was scored by ex-Carlisle youth player Dillon Morse.
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