Gary O'Neil took advantage of a defensive mistake to earn Portsmouth a late point at Sheffield United.
The midfielder pounced on a mix-up between Blades defender Claude Davis and keeper Paul Gerrard, to tap in from eight yards nine minutes from time.
Stephen Quinn gave United the lead when he curled in a 20-yard free-kick.
Pompey also went close through Andy Cole, with a firm drive, while Matthew Taylor and Nico Kranjcar shaved the post with their low efforts.
History was very much against Portsmouth. The south-coast side had not recorded a win at Bramall Lane since 1955, and had lost 19 of the last 22 games played there.
But it was unlikely Pompey boss Harry Redknapp would have cared in the slightest for statistics, with his side 10 places above the Yorkshire side going into the match and favourites to claim their 11th win of the campaign.
The Blades had the best of the first half and new signing Jon Stead, who was impressive throughout the match, almost scored a debut goal in the first minute but headed his effort from Derek Geary's cross fell straight into the hands of David James.
Stead, who signed for £750,000 this week, then set up strike-partner Rob Hulse but his tame shot from 12 yards was saved comfortably by the Pompey keeper.
The pressure from the front pair paid off midway in the half when 20-year-old Quinn curled in a lovely free-kick to give the Blades the lead.
Portsmouth fought back well after the break and dominated much of the possession.
Pedro Mendes began to conduct proceedings in the middle of the park for the visitors, while his team-mates also pulled up their socks peppering the edge of the Blades area with a variety of high a low balls.
It seemed it was not going to be Portsmouth's day when Taylor and then Kranjcar beat Gerrard, but also his left-hand post by inches.
But his side persisted and finally got their reward thanks to a horrendous lack of communication between Davis and Gerrard.
With Benjani closing down the pair, they left it to each other to do something about the loose ball.
Unfortunately for the Blades, O'Neil was far more alert and tucked in to make those Bramall Lane statistics a little bit more pleasing to the eye for Redknapp.
Sheffield United boss Neil Warnock:
"We were sloppy, but we didn't deserve to get punished like that.
"Claude is inconsolable. Hopefully he'll learn from his mistake."
Portsmouth boss Harry Redknapp:
"We are still in the top six where we have been all season and if we could stay there then it would be fantastic.
"The top four will be as you are - they are on another level. It's then going to be close behind that pack."
Sheff Utd: Gerrard, Kozluk, Lucketti, Davis, Geary, Gillespie, Jagielka, Montgomery, Stephen Quinn (Tonge 85), Hulse, Stead (Nade 77).
Subs Not Used: Bromby, Alan Quinn, Kazim-Richards. Goals: Stephen Quinn 22.
Portsmouth: James, Johnson, Primus (Kranjcar 54), Campbell, Traore, O'Neil, Davis (Mwaruwari 74), Pedro Mendes, Taylor, Cole, Kanu (Hughes 88).
Subs Not Used: Ashdown, Griffin.
Booked: Primus, O'Neil.
Goals: O'Neil 81.
Att: 30,269
Ref: L Probert (Gloucestershire).