By Dan King - Newcastle United Club Reporter
He played for Brighton as they lost 3-0 to Championship leaders Southampton in a south-coast derby at St. Mary's.
Ricky Lambert had already scored once, with a towering header, when referee Peter Walton awarded the first spot-kick, which was dispatched by Lambert.
And despite making a fine save to deny the striker a hat-trick, Harper was eventually beaten again from the spot by Lambert.
The result means Brighton have won just one of their last 12 games, although Harper has kept two clean sheets in five games since joining up with Gus Poyet's side.
Kazenga LuaLua was an unused substitute for the Seagulls.
Ole Soderberg, meanwhile, saw five goals fly past him as Chesterfield lost 5-2 at Oldham.
The Spireites were 3-0 down inside 17 minutes and although Soderberg had little chance with any of those goals, he would have been disappointed to lose out to Robbie Simpson who got to Jonathan Grounds' sloppy backpass ahead of the Swedish under-21 international goalkeeper for his third of the game.
Former Magpies man Shefki Kuqi made it five on 58 minutes.
Jak Alnwick helped Gateshead gain a 1-1 draw at Alfreton in the Blue Square Bet Premier - ex-United junior Chris Moore scoring the Heed goal - but Jeff Henderson played no part, having suffered a minor hamstring strain in midweek.
That also caused him to miss Newcastle's Reserve game at Sunderland - both Henderson and Alnwick can turn out for Willie Donachie's second-string if games don't clash with Gateshead matches under the terms of their youth loan agreements.
It was left to Fraser Forster to pick up a win for the Magpies loanees, keeping a welcome clean sheet in a 2-0 win at Inverness.