Pompey fought from behind to beat Tottenham’s under-21 side and secure top spot in Southern Group A of the Checkatrade Trophy.
Phoenix Patterson had given the visitors the lead against the run of play in a first half that could best be described as flat.
But the Blues were much improved after the interval and Andre Green opened his account for the club to get them back on level terms.
There was only going to be one winner from that point, with substitutes Gareth Evans and Oli Hawkins completing the job before Harvey White grabbed a late consolation.
Kenny Jackett changed his entire starting 11 following Saturday’s comfortable FA Cup victory at Maidenhead.
Bradley Lethbridge was handed his debut up front, while fellow academy player Haji Mnoga – who appeared in the previous Checkatrade Trophy game at Crawley – had another chance to impress.
There were also starts for on-loan wingers Green – back from a knee injury – and David Wheeler, with Louis Dennis completing the forward line.
With it being Pompey’s nearest match to Armistice Day, the club commemorated the occasion before kick-off.
Wreaths were laid by both captains and a video of D-Day veteran John Jenkins MBE reading the Ode of Remembrance was played on the big screen.
The sides – with the hosts having poppies embroidered into their shirts – then lined-up for a minute’s silence, accompanied by the Last Post.
There was not much to excite a smaller than usual crowd in the first half, although the hosts were largely in control.
They did not do much to threaten Alfie Whiteman, however, with the keeper making a comfortable save to deny Green.
And Tottenham broke the deadlock against the run of play on 20 minutes, as Patterson latched on to a through ball and bore down on goal.
Luke McGee was quickly off his line to make the save, but the loose ball was collected by the winger, who slotted home.
Lethbridge was causing a nuisance, although after doing well to bundle his way into the box, he was eventually crowded out.
Dennis also had an effort blocked, while Ben Close fired narrowly over after winning the ball on the edge of the box.
There was little threat at the other end of the pitch and when Kazaiah Sterling broke clear, skipper Christian Burgess was quickly across to make a perfectly-timed sliding challenge.
The hosts perked up a bit towards the end of the half and Wheeler glanced a corner inches past the post, while an inventive Burgess header drew a save from Whiteman.
Half Time: Pompey 0 Tottenham U21 1
The action had dragged before the interval, but it soon livened up after it, with a series of chances arriving at both ends of the pitch.
Anton Walkes – playing against his former club – was first to try his luck, with a low effort that took a slight deflection to divert it just off target.
But an equaliser did arrive moments later, as a corner from Dennis was nodded on by Burgess and GREEN forced the ball home at the far post.
Tottenham came close to an instant reply, though, with McGee getting down well to tip Patterson’s shot around the post.
And a breathless period of play was completed by Close seeing his deflected effort held by Whiteman.
Pompey were seeing more of the ball, but it still took another superb challenge by Burgess inside the box to stop Sterling getting a shot away.
Jackett made all three of his substitutions on 65 minutes, with Green, Lethbridge and Mnoga replaced by Evans, Hawkins and Matt Clarke.
And EVANS’ first contribution was to fire the Blues into the lead, smashing a free-kick through the wall after Dennis had been fouled on the edge of the box.
The game slowed slightly after that, although it was still the hosts who were well on top as the action neared a conclusion.
They made sure of the victory on 81 minutes, with Wheeler getting free down the right and cutting the ball back for HAWKINS to prod home from close range.
White did pull one back with a fine free-kick after Danny Rose had committed a foul, although Tottenham were unable to find a leveller.
The visitors could, however, console themselves with the fact that Crawley’s defeat to Gillingham means they join the Blues in the knockout stages.
Pompey (4-2-3-1): McGee; Mnoga (Clarke 65), Burgess (c), Walkes, Haunstrup; Close, Rose; Wheeler, Dennis, Green (Evans 65); Lethbridge (Hawkins 65)
Goals: Green 50, Evans 69, Hawkins 81
Subs not used: MacGillivray, Brown, B.Thompson, Smith
Tottenham U21 (4-2-3-1): Whiteman; Lyons-Foster, Tanganga, Marsh (c), Brown; Bowden (Shashoua 89), White; Oakley-Boothe (Parrott 86), Duncan (Richards 75), Patterson; Sterling
Goals: Patterson 20, White 90
Subs not used: Glover, Markanday
Referee: James Linington
Attendance: 3,138 (125 away fans)