Tommy Conway's 90th-minute penalty on his home debut denied Portsmouth a first victory since promotion as they drew 2-2 at Middlesbrough in the Championship.
Portsmouth went ahead after just 102 seconds as Christian Saydee fired in unmarked after a quick break, but the lead last just 10 minutes as former Pompey favourite Matt Clarke headed home a corner.
However, Saydee - who had only scored two league goals for Portsmouth since joining from Bournemouth last summer - got his second when he pounced on a 25th-minute defensive error as the visitors led an action-packed first half.
Boro upped the pressure after the break and spurned numerous chances before Conway's late spot-kick ensured a share of the points after Isaiah Jones had been fouled by Owen Moxon.
The first meeting between the sides in almost 12-and-a-half years started superbly as Pompey hit Boro on the break inside the second minute as Callum Lang crossed for the unmarked Saydee to convert from close range.
But Clarke - who played 175 games for Pompey over a four-year spell that ended in 2019 - headed in Finn Azaz's corner with Portsmouth goalkeeper Will Norris needing treatment in the aftermath after colliding with the post as he tried in vain to save.
Boro only had themselves to blame as they went behind again 15 minutes later as a long throw into the area looked as though it would be dealt with by Clarke, only for goalkeeper Seny Dieng to come out and try and clear, allowing Saydee to capitalise on the confusion and roll the ball home.
Clarke made amends with an excellent block to deny Saydee a hat-trick soon after before Boro saw Emmanuel Latte Lath have an effort cleared off the line by Jordan Williams while Norris did well to deny him as he broke through on goal deep into first-half stoppage time.
The hosts stepped up their intensity early in the second half as Aidan Morris, Hayden Hackney and Delano Burgzorg went close within eight minutes of the restart.
Azaz forced Norris into an excellent save from from a tight angle while the Pompey goalkeeper instinctively tipped over a powerful 72nd-minute Hackney half-volley.
Michael Carrick's side again went close when Latte Lath narrowly missed getting on the end of Conway's cutback with eight minutes to go.
But their pressure finally told in the final moments as Anfernee Dijksteel's precision pass found Jones, who was upended by Moxon and Scotland forward Conway sent Norris the wrong way from 12 yards as Portsmouth drew their third game out of three since returning to the second tier.
Middlesbrough head coach Michael Carrick told BBC Radio Tees:
“For how well we’ve played for the most part and created so many opportunities, I thought we had a spell around the second goal for maybe five or 10 minutes where we lost the focus or intensity and lost our way a bit, but other than that I thought we were really good.
“We can definitely make it easier for ourselves, we’re doing so many good things in the game and a lot of difficult things really well.
“Some of the what are deemed simple things we were just getting wrong are small moments, which cost us, but we'll put that right.”
Portsmouth manager John Mousinho told BBC Radio Solent:
“We're obviously going to be disappointed - a bit like Elland Road where we came away from the game going into injury time with the lead and it transpires that we end up drawing the game.
“There’s a lot of disappointment from that point of view, but from the balance of the game Middlesbrough deserved to win it and we didn’t quite do enough in the second half to hold on to our lead.
“We played really well in the first half for large spells, I thought thoroughly deserved the lead going into half-time
“I think naturally when you come away to places like this you do sit deep and probably there’s a bit too much panic on the ball, we didn’t really quite settle down enough.
“It’s really good lesson as we go up through the levels and play against sides likes this that when we’re on it we can compete, but as soon as we drop even five per cent then sides like this do punish you.”