Both attackers were at the heart of a spectacular Blues performance that saw them end their seven-game winless run in the league and hand the high-flying Black Cats a reality check.
Harness opened the scoring in the 4-0 rout when he expertly fired home from the edge of the box in the 19th minute.
And Curtis provided the assist to John Marquis’ first of the afternoon when the Blues striker glanced home his whipped free-kick.
In fairness, the duo have had their ups and downs already this season.
But former Pompey defender Robinson – who was acting as a pundit for BBC Solent on Saturday – was singing their praises at full-time as they continued their recent good form.
He said: ‘Curtis and Harness are up there with some of the best players in the division.
‘They’ve shown that over the previous seasons and it’s only been flashes for Pompey this season really.
‘I think what you’ve seen from them today (Saturday) against Sunderland, who are top of the league for a reason and a big club in the division, we’ve seen a top performance from them and what they are capable of.
‘They probably wanted to prove themselves and it all came together.
‘It all worked in Pompey’s favour and I’m just really hopeful that this can be the springboard for Pompey moving into the season.
‘Hopefully the bad run of form is behind them now, and everyone goes through bad spells over the course of the season.
‘They’re adapting to the three at the back and hopefully this win can give them the confidence to move forward with it.’
Curtis and Harness weren’t the only ones to catch Robinson’s eye against Sunderland.
He was also impressed by John Marquis’ return to form in front of goal – and said he set the tone for the rest of his from the opening whistle.
‘It was exactly what Marquis needed. Two goals and the manner of his performance was excellent.
‘Sometimes I think he can look slightly scrappy in his forward play but he is always chasing and hustling defenders.
‘From when Sunderland first rolled it out during the first few minutes he was on them, and everyone else was the same.
‘I’m really pleased for John and hopefully now that’ll settle him down and give him the confidence to start scoring goals on a regular basis.
‘They (Pompey) showed that they were hurting and put that into their performance from the first whistle and put in the kind of performance that the fans demanded.
‘It got the stadium and everyone behind them and got everyone going. It was an excellent afternoon's work from them.’