Damien McCrory is still waiting for his first outing in a Portsmouth shirt after seeing his new loan side beaten by Rotherham United in League One on Sunday from the bench.
McCrory - the longest-serving Burton Albion player still with the club - joined Pompey on loan until January on transfer deadline day, and he was included in the hosts' squad at home to Rotherham at the weekend.
But a 36th-minute strike from Jon Taylor meant defeat for Portsmouth, with the Millers securing their first away league win in 27 attempts.
The result leaves Pompey 16th in the third-tier table, with five points to their name from five games.
Ex-Albion captain John Mousinho, meanwhile, was not in the Oxford United squad as they drew 1-1 at MK Dons in the same division, two days after the Brewers stalwart left the Pirelli Stadium to join the Us.
In League Two, Marcus Harness' Port Vale dropped into the bottom two after a 1-0 defeat at home to Notts County.
The Brewers winger started the game and played until the 66th minute when he was substituted - a decision that did not please the home support, according to the Stoke Sentinel's player ratings from the game, which also suggested Harness' work rate has made him a popular figure with the Vale supporters.
Away from the EFL, Marcus Dinanga was again on target for AFC Telford United as they fell just short of a remarkable comeback at home to Blyth Spartans in National League North.
Trailing their visitors 3-0 with 25 minutes to play, Dinanga rose highest to power home a header and spark a response from the Bucks with his third goal in five games for the club since joining on a season-long youth loan deal.
Elliot Newby then got the hosts to within a goal of the comeback - but they could not complete the job and fell to a fifth defeat from eight league outings this term.
Jayden Cotterill made his Matlock Town debut in Saturday's 3-2 FA Cup first qualifying round defeat to Haughmond FC.
The Albion full-back - who signed his first professional deal with the club earlier in the summer - has joined the Gladiators on an initial month-long loan , meeting up with ex-Brewer Glenn Kirkwood following a successful spell at Causeway Lane for Dinanga last season.
Fellow Burton defender Ryan Delaney, meanwhile, started as Cork City fell to only their third League of Ireland Premier Division defeat of the season.
City were beaten 3-1 at Shamrock Rovers, but are still 14 points clear at the top of the table, with the campaign coming to an end on October 27.
That is when Delaney's loan stint at the club will also come to an end.