Derby fielded a new-look strike force of Chris Martin and Johnny Russell for the clash, while Blackburn included Tommy Spurr in their starting lineup despite him joining the Lancashire club just two days ago.
The weather was more fitting of a midwinter match as the teams entered the pitch amidst torrential rain.
Alan Judge came within whiskers of opening his Blackburn account on his debut when his curling effort bent inches wide of Lee Grant's post.
The away side's record signing, Jordan Rhodes, was denied the opener when his header was cleared off the line by an alert Craig Forsyth.
Ruben Rochina left the field in the 40th minute with a suspected dislocated shoulder, and Blackburn's afternoon went from bad to worse after a moment of madness from Alex Marrow.
The young defender handled a free kick and gifted the home side a penalty, which was duly dispatched by Russell.
Best was Blackburn's biggest threat in the second half, as the Republic of Ireland international hit both the bar and the post.
With little more than two minutes remaining, Best secured a dramatic draw for the away team when he wrapped his foot around the ball and sent it beyond the despairing reach of Grant.