Derby defender Andy Todd scored his first goal for 17 months to deny Portsmouth striker John Utaka his own moment of debut glory in a 2-2 draw between the teams at Pride Park.
After Benjani Mwaruwari had cancelled out Rams captain Matt Oakley's fourth-minute opener later in the first half, the game then exploded late on with two goals in two minutes.
Utaka, a transfer from Rennes this summer, appeared to have grabbed the limelight with an 82nd-minute strike.
However, within seconds defender Todd, a free transfer capture from Blackburn, clinched a deserved point for Derby on its return to the Barclays Premier League with a diving header.
Manager Billy Davies' side was certainly excellent value, and on this showing have every chance of proving the bookmakers wrong as it is favourite for an instant return to the Championship.
These are early days, of course, with the objective for both teams in stark contrast as Derby are banking on mere survival, while the visitors are targeting UEFA Cup football.
Derby's season was barely four minutes old when goalkeeper Stephen Bywater punted a long goal-kick upfield where Steve Howard managed to outjump Sol Campbell, who was wearing the captain's armband for the first time.
Howard's header looped into space with barely a blue shirt within yards of Oakley who was given a clear sight of David James' goal.
The former Southampton midfielder, who scored on his last outing against Pompey in January 2005 when he helped knock them out of the FA Cup, made no mistake with a crisp right-foot drive from 15 yards.
Pride Park erupted and from that moment it appeared as if another of the league's new boys would claim three points on the opening day, as Sunderland had remarkably done against Spurs earlier in the day.
But then Portsmouth started to find their feet, and after Bywater had denied Pedro Mendes on the half volley from 25 yards, Redknapp's side were back on level terms in the 27th minute.
New boys Sulley Muntari and David Nugent played their part in teeing up Mwaruwari, who had scored just six goals in his previous 50 appearances.
The Zimbabwe striker first shimmied his way past Andy Griffin, a free transfer signing from Portsmouth, before passing the ball underneath a slow-on-the-shot Bywater.
After the interval the chances continued to fall Derby's way but the Rams appeared as if they would pay for their missed opportunities when another two of Pompey's new faces in Sylvain Distain and Hermann Hreidarsson combined to set up Utaka.
But the Rams refused to go under, and sparked by 75th minute substitute Gary Teale, it was the Scotland international who laid the ball on a plate for Todd to grab a share of the spoils.
English Premiership
Derby 2 (Oakley 5, Todd 84)
Portsmouth 2 (Mwaruwari 27, Utaka 83)