Michael Appleton rued Lincoln’s set-piece defending as his Fratton Park return was a miserable one.
The former Pompey boss saw his Imps fall to a 1-0 loss against the Blues last night.
John Marquis netted the only goal of the League One encounter in the 28th minute when he profited from Christian Burgess’ saved header to finish from close range.
Burgess also had an effort save from another Gareth Evans delivery in the second half, only for visiting keeper Josh Vickers to make a fine stop down to his left.
Appleton, who was in charge at PO4 for a year after succeeding Steve Cotterill in November 2011, felt Pompey were going to target Lincoln from corners and free-kicks.
The Imps manager recognised Kenny Jackett’s men had a significant height advantage they’d look to put to good use.
And while Appleton didn’t expect many of the aerial duels to be won, he wanted his side to show more resistance than they did in the box.
The ex-Oxford United boss told Lincolnshire Live: ‘We’ve been done on a set-play which is very disappointing and I’ve made my feelings clear about that.
‘We knew it was coming. They’ve got some big, big players and we haven’t.
‘I was more disappointed that it was a free header, rather than him winning the header.
‘When the likes of Burgess and Sean Raggett go in there, we might not be favourites to win the header but we want to make it as difficult as we can to get good contact.’
Pompey’s win moved them up to 16th after collecting 16 points from 12 games. They head to Bristol Rovers on Saturday.
Lincoln, meanwhile, have won just two of their past 15 in all competitions and 15th in the table, having garnered 17 points from 15 matches.