Conor Chaplin bagged a brace as Pompey drew 3-3 at Sligo in their opening pre-season friendly of the summer.
Gary Roberts also found the target in a testimonial match for long-serving Rovers favourite Gavin Peers.
That saw the visitors coast to a three-goal lead, only for the Irish outfit to hit back with three of their own after the break – including a spot-kick from man-of-the-moment Peers.
It was still an enjoyable return to The Showgrounds for Cook, though, who won three trophies when he managed the Irish club between 2007 and 2012.
There was certainly a testimonial feel to the first half, as the hosts fielded a side made up former team-mates of Peers.
One of them was Kieran Djilali – who had a short spell with the Blues in 2012 – while the brother of Westlife star Mark Feehily also featured.
Pompey, unsurprisingly, dominated before the break and they took the lead with just nine minutes on the clock.
Chaplin did well down the right and was able to pull the ball back for ROBERTS to tap home from just a yard out.
And he was able to return the favourite soon after, with CHAPLIN free to capitalise when the midfielder’s path to goal was blocked by keeper Ciaran Kelly.
Trialist stopper Michael Crowe was largely untroubled at the other end and Christian Burgess stopped him from having to make a save by blocking Djilali’s effort.
Djilali soon made a sheepish exit, however, as following a flurry of substitutions, referee Alan Kelly had failed to spot that Sligo had 12 men on the pitch.
Jack Whatmough did well to deny the Irish side on 38 minutes, charging across to halt a quick counter-attack.
Instead it was Pompey who added to the scoring soon after, with Roberts and CHAPLIN again combining, and the latter neatly lifting the ball home.
There were two chances to increase the lead further before the interval, but Roberts and Milan Lalkovic both narrowly failed to find the target.
Half Time: Sligo 0 Pompey 3
Peers remained on the pitch for the second half and was this time joined by 10 of his current team-mates.
Cook also rung the changes, with Roberts and Chaplin the only Blues players not to be given a rest.
Sligo almost pulled a goal back on the hour mark, but Kieran Sadlier’s drive was beaten away by replacement keeper Eric Grimes and the winger sent his follow-up effort into the side netting.
Raffaele Cretaro then wasted a great opportunity to get on the scoresheet, missing a free header at the far post.
But Sligo did have a goal on 70 minutes and – although it appeared rather soft – there were no complaints when a penalty was awarded for a challenge on Phil Roberts by Tom Davies.
That gave Peers the chance to score from the spot and he confidently slotted the ball into the bottom corner before being withdrawn to a standing ovation.
It was soon Pompey who were back on the attack and Chaplin saw an effort blocked at point-blank range following good work from Kyle Bennett and Carl Baker.
With a total of 52 players used, the game had understandably lost a bit of impetus as it coasted towards a conclusion.
But it sparked back into life towards the end as the impressive Sadlier scored twice in quick succession to draw the hosts level.
First he poked home from close range following good work down the right by Cretaro and then rifled home the equaliser seconds later.
But more important for Cook was the chance to see his squad get some minutes under the belt, while Peers was rightly lauded for his loyalty to Sligo.
Sligo first half (4-4-1-1): Kelly; Keane, Peers (c), Burns (Flannery 24), Foy (McCartney 24); Djilali (McTiernan 24), O’Grady (Judge 31), Ventre, Dillon (Mansaram 31); Ndo (Feehily 33); Elding (McNamara 24)
Sligo second half (4-4-2): Schlingermann; Adebayo-Rowling, Peers (c) (Trialist 70), Boylan, Keohane; Kearns, Roddan, Russell (Lines 79), Sadlier; Cretaro (Place 86), Roberts
Goals: Peers 69 (pen), Sadlier 85, 87
Pompey (4-2-3-1): Crowe (trialist) (Grimes (trialist) 46); Talbot (Sessegnon (trialist) 46), Whatmough (Davies 46), Burgess (Barton 46), Haunstrup (Stevens 46); May (Close 46), Doyle (c) (Rose 46); Tollitt (Baker 46), Roberts (Konsiembo (trialist) 62), Lalkovic (Bennett 46); Chaplin (Tollitt 79)
Goals: Roberts 9, Chaplin 17, 40
Referee: Alan Kelly