Bishop struck deep into stoppage time to cancel out James Collins’ 86th-minute penalty in front of a crowd of 27,999.
That stretches the Blues’ unbeaten run to 18 games - the longest unbroken stint in the country.
The point was the least John Mousinho’s side deserved, who were excellent for decent periods in front of 3,000 travelling fans.
Pompey played some lovely stuff and exercised control of the game and arguably deserved a greater reward.
They’ll take a point in those circumstances, however, as they passed the stiffest test of their credentials to date.
The Blues made two changes from the side who beat Peterborough with the injured Christian Saydee and suspended Joe Morrell replaced by Alex Robertson and Paddy Lane.
Pompey had an early let-off when a wayward Conor Hourihane shot cannoned off Martyn Waghorn and cracked the bar.
Some lovely build-up play from Pompey then freed Lane, but his shot at Joe Wildsmith was weak.
Waghorn cleared off the line in the 17th minute when Colby Bishop met Zak Swanson’s cross with a header.
Pompey were playing some lovely stuff and Abu Kamara’s ingenuity freed Bishop in the box, but he took a touch instead of finishing first-time allowing his shot to be deflected over.
It was a good first 45 minutes from the Blues, however, which had silenced the home crowd.
And the second half continued with the same pattern, as Lane angled a 15 yarder just wide in the 53rd minute after a fine move involving Poole and Bishop.
Pompey looked threatening going forward and saw Whyte hit a 20 yarder in the 59th minute, but Bishop’s deflection diverted the ball at Wildsmith.
Derby then mustered some threat with Mendez-Laing’s 20-yard effort deflected over, but Pompey replied through Ogilvie’s header which Wildsmith clutched away from the top corner.
Tino Anjorin was handed his debut in the 71st minute replacing Kamara.
Whyte then saw his low drive from the edge of the box saved by Wildsmith to his left.
There was a late dagger in Pompey’s heart as Poole was adjudged to have handled Tom Barkhuisen’s cross and James Collins dispatched the penalty.
Then sub Terry Devlin somehow headed over from close range.
There was more late drama, however, deep in stoppage time as Bishop prodded home Whyte’s cross after it was helped on by Devlin.