Portsmouth survived a second-half bombardment to hold Premiership leaders Arsenal and maintain their unbeaten record after five matches.
Arsenal, who dropped their first points of the season, now head Manchester United by one point.
Portsmouth, who are now fourth, even took the lead through Teddy Sheringham before Thierry Henry levelled with a twice-taken penalty.
The busy Amdy Faye disrupted Arsenal's rhythm and it was 20 minutes before Ray Parlour managed the Gunners' first shot.
Six minutes later, ex-Tottenham and Manchester United star Sheringham stunned the home crowd with a clinical near post header from Steve Stone's cross.
The leaders levelled five minutes before half time after referee Alan Wiley ruled that Dejan Stefanovic had fouled Robert Pires. Henry kept his nerve to score with his second kick after encroachment at his first effort.
Portsmouth striker Yakubu Ayegbini missed two chances soon after the interval, shooting wide from promising positions.
Harry Redknapp's side had to show their resilience in the closing minutes as Patrick Vieira drove Arsenal forward.
Stefanovic and Arjan de Zeeuw were solid in the centre and the Gunners tended to over-elaborate. But Shaka Hislop still had to tip over from Dennis Bergkamp and Henry.
Vieira headed wide from a corner and Kolo Toure fired Sylvain Wiltord's header over as Arsenal ended the game frustrated.
Redknapp rapped referee Wiley after the game saying: "We were in control for the first 30 minutes. But the game hinged on the penalty. I thought it was a wrong decision.
"I didn't see any foul by Stefanovic. In fact I thought the referee was going to give Pires a yellow card for diving. The players were amazed.
"I know referees don't do these things deliberately. But they seem to have got a lot of these decisions wrong already this season.
"I was pleased with the way we played. We rebuilt the team last season and we've done it again the summer. We've brought in new players without breaking the bank."