Cheltenham 2 Portsmouth 1: Neil Allen's verdict - Blues' arch nemesis strikes again as promotion concerns mount

For more than a decade he's been the scourge of Pompey, a manically cackling, moustache-twirling figure brimming with villainous intent and mischievous merriment.

If indeed this is to finally be a parting of the ways and a campaign in which a Championship return is secured, perhaps it was fitting their arch nemesis wreaked customary havoc. Call it his last laugh, if you will.

Liam Sercombe has been cast as the Blues' chief tormentor during 12 agonising seasons occupying League One and below - and doesn't he just revel in the responsibility.

It's not merely the midfielder's haul of six goals in 17 career appearances against Pompey which sends shivers down the spine. He has now drawn blood with each of four different clubs - Exeter, Oxford United, Bristol Rovers and Cheltenham.

What's more, five different Blues managers/head coaches have been on the receiving end since opening his account in February 2014, of which three of his goals proved match winners.

Saturday marked John Mousinho becoming the latest to incur Sercombe's wrath, striking twice in three minutes to inspire a 2-1 Cheltenham triumph few would have anticipated, including those attending.

Obviously this is ludicrously early to pinpoint the ever-tiresome 33-year-old's latest intervention as extinguishing Pompey promotion aspirations.

Nonetheless, Mousinho's men have been noticeably staggering and swaying for several weeks. Now a familiar black-hearted character has cast more darkness over where there was once light.

That's one win from their last five league matches amid a kindly festive fixture list when many would have expected a full house of victories - or mightily close.

Instead, Pompey are now two points clear of second-placed Bolton having played two games more, while Peterborough, Derby and Oxford and looming ever closer in the rear-view mirror.

Despite retaining a strong position as they head into their final 20 matches, concern is understandably growing, particularly with Alex Robertson now sidelined for a period of absence still to be clarified.

The impressive Australian damaged his hamstring in training on Thursday, signifying a huge blow. With Tino Anjorin also potentially not returning until March, the likelihood is an attacking replacement must now be sought as a matter of urgency during the January transfer window.

Against Cheltenham, Gavin Whyte was brought in to deputise for Robertson, subsequently attracting praise from Mousinho over his Whaddon Road performance on a 25th outing of the campaign.

However, at the season's halfway mark, the summer marquee signing has been a tremendously disappointing capture and cannot be expected to provide the same calibre of performances as his predecessor. At least not based on evidence to date.

With Scully still feeling his way back following knee surgery and long-term absence, Josh Martin a stop-gap recruit who cannot get a game, and Kusini Yengi on international duty at the Asian Cup, suddenly Pompey's once burgeoning attacking options are drying up.

Ironically, the primary cause of the 2-1 defeat to the struggling Robins were two wretched pieces of defending after Pompey had broken the deadlock when Tom Bradbury put through his own net under pressure from Colby Bishop.

Moments later, a long Cheltenham throw was launched from the left and the unmarked Sercombe was able to take a touch on his chest before hooking the ball left-footed into the net.

His second on 54 minutes was even more disastrous for the Blues. Joe Morrell played the ball back to Conor Shaughnessy, who had plenty of time to take a touch, before inexplicably attempting to take on George Lloyd inside the penalty box.

Failing to get past him, the ball ran helpfully free, allowing Cheltenham's number eight to crash a fierce first-time right-footed effort past Will Norris to make it 2-1 to the hosts.

Mousinho described it as a 'mad five minutes' - and it would prove decisive.

Either side of that brief period, the Blues were in control, dictating proceedings and extremely comfortable in defence. However, failure to truly test opposition keeper Luke Southwood throughout the match was critical.

Granted, there were two strong penalty shouts on Abu Kamara, who was harshly booked for diving for one of them, while substitute Scully suffered the same yellow card fate after believing he had been pulled back inside the box.

Yet while gifting Cheltenham two goals at one end, the Blues weren't anywhere near ruthless enough to capitalise at the other, epitomised by Bishop sending a glorious headed chance over the bar in the dying seconds.

Sercombe, who turns 34 in April, will most likely still be around next season. It's over to Pompey to guarantee they won't meet him ever again.