Pompey did all the early running but found themselves 2-0 down before half-time as Boro hit the visitors on the break. But Steve Cotterill's side managed to show some resolve to claw their way back into the contest to level five minutes before the end in controversial circumstances.
Matthew Bates' second ever goal for his home-town club gave Boro the lead after 30 minutes and a Barry Robson penalty five minutes before half-time gave the hosts a 2-0 lead. But a David Nugent header from a Liam Lawrence cross on the hour pulled the visitors back into the contest, before the latter equalised from the penalty spot, five minutes from time, after the referee's assistant spotted an off the ball incident, which resulted in Robson being sent off.
Strachan made several changes to the side which lost at Derby in midweek but he suffered a blow after only six minutes when Kevin Thompson limped off following a late challenge from Michael Brown. Thompson was rushed to hospital to have an X-ray immediately after being substituted.
A fine run down the left by Nugent saw the visitors carve open the first opportunity but, fortunately for the home side, Stoke loan man Lawrence skied his effort over the bar, while the influential Robson stung the fingers from Jamie Ashcroft in the 17th minute as both sides went toe to toe in the opening exchanges.
Boro shot stopper Jason Steele was then called into action and tipped around the post from a Lawrence free-kick moments later. And once again Ashdown did likewise from a Kris Boyd free-kick.
But on the half-hour mark, from the resulting Robson corner kick Bates smashed through a crowded penalty area for the Teessiders to take a lead.
Five minutes before the break Boro went 2-0 up from the penalty spot through Robson after Scott McDonald was brought down by Aaron Mokena.
Stephen McManus maintained the Boro momentum after the break and should have increased the lead with a little over three minutes on the clock, while moments later Boyd wasted three efforts in consecutive minutes. One, a weak header into the goalkeeper's arms, while his second and third efforts flashed wide of the post.
The visitors were certainly the better side after the goal and Boro were hanging on for long periods. But the home side showed they were still dangerous on the break when MacDonald brought the best out of Ashcroft. But all of Boro's good work was undone when the referee's assistant spotted an off the ball incident, where Robson was dismissed, and a penalty was awarded which the dangerous Lawrence despatched to earn a share of the spoils for the south coast club.
Middlesbrough Steele, McMahon, Wheater, McManus, Bates, Thompson (Mickael Tavares 8), Robson, O'Neil (Lita 77), Halliday (Bailey, 52) Boyd, McDonald.
Subs not used: Danny Coyne, Joe Bennett, Tarmo Kink, Seb Hines Portsmouth: Ashdown, Ward, Mokoena, Rocha, Dickinson, Lawrence, Mullins, Brown, Utaka, Nugent, Kitson Subs not used: Flahavan, Sonko, Ritchie, Ciftc, Kanu, Hughes