Match ends, Blackpool 0, Derby County 1.
Chris Martin scored a late penalty as Derby County overcame a battling Blackpool 1-0 to go top of the Championship table.
Martin converted an 81st-minute spot kick after Johnny Russell had been fouled by Tony McMahon.
Blackpool had the best opportunities in the first half but Delfouneso missed their best chance when he screwed a shot over the bar.
The result means Derby have won five out of their last seven games.
The Rams are also unbeaten in the last 10 matches, but were made to work for the win against a spirited Blackpool.
Jose Riga's side defied their lowly league position to shade the better of the first-half chances.
Ishmael Miller went close to opening the scoring on 10 minutes when he whistled a shot past the post with a long-range effort.
On-loan Derby goalkeeper Jack Butland was also forced in to a smart save to block a shot from McMahon at his near post four minutes later.
But Delfouneso spurned the clearest first-half opening as he shot over from the centre of the area on 25 minutes.
Derby began to grow into the game and Jeff Hendrick almost gave them the lead before half time, but Blackpool goalkeeper Joe Lewis tipped his header from Cyrus Christie's cross over the bar.
The visitors' Donervon Daniels had the first chance of the second half and headed wide from a corner.
Russell was denied by another smart save from Lewis when his 25-yard shot was tipped over the bar on 66 minutes.
But Russell was to play a part in the game's decisive moment as McMahon tripped him on the edge of the area as he looked to supply another cross from the right.
Martin stepped up to decisively smash a right-foot shot from the spot past Lewis.
Craig Bryson looked to be through on goal to seal the points for Derby with two minutes left, but was denied by some last-ditch Blackpool defending.
Blackpool manager Jose Riga: "The players I have at this moment, some of them have not a lot of experience in the Championship and I need some players to help all the team because everything will be easier then.
"It is not the first time this season (we've got nothing). We created the best opportunities during the first 25 minutes and we had to score.
"If you can't make the most of these moments when you are good but bottom of the table, you cannot hope a lot."
Derby manager Steve McClaren: "I believe the squad is stronger than last season. I mean we're leaving out players and bringing in internationals in the likes of Jeff Hendrick. That's pleasing.
"It's the maturity of the group too. We wouldn't have got six clean sheets on the bounce last season.
"We were very innocent, running about all over the place playing good football and sometimes not getting the results because of it.
"The maturity of the squad, knowing how to win and what it takes, there's determination in there. We were a young team, we still are a young team but they are showing that maturity."
- 29McMahonBooked at 73mins
- 24LundstramSubstituted forMendyat 84'minutes
- 4PerkinsBooked at 90mins
- 11OrlandiBooked at 17minsSubstituted forZokoat 67'minutes
- 23OriolSubstituted forMellisat 67'minutes
- 2ChristieBooked at 33mins
- 19HughesSubstituted forBrysonat 75'minutes
- 44IbeSubstituted forBestat 75'minutes
- Kevin Wright
- Shots on Target
Second Half ends, Blackpool 0, Derby County 1.
David Perkins (Blackpool) is shown the yellow card for a bad foul.
Jeff Hendrick (Derby County) wins a free kick on the right wing.
Foul by David Perkins (Blackpool).
Foul by Chris Martin (Derby County).
Tony McMahon (Blackpool) wins a free kick in the defensive half.
Craig Forsyth (Derby County) wins a free kick in the defensive half.
Foul by Jacob Mellis (Blackpool).
Attempt missed. Jeff Hendrick (Derby County) right footed shot from outside the box is too high. Assisted by Chris Martin.
Cyrus Christie (Derby County) wins a free kick on the right wing.
Foul by Nathan Delfouneso (Blackpool).
Attempt blocked. Craig Bryson (Derby County) left footed shot from the centre of the box is blocked. Assisted by Cyrus Christie.
Foul by Jeff Hendrick (Derby County).
Jacob Mellis (Blackpool) wins a free kick in the defensive half.
Foul by Leon Best (Derby County).
Donervon Daniels (Blackpool) wins a free kick in the defensive half.
Substitution, Blackpool. Formose Mendy replaces John Lundstram.
Attempt missed. John Lundstram (Blackpool) right footed shot from outside the box is high and wide to the right.
Goal! Blackpool 0, Derby County 1. Chris Martin (Derby County) converts the penalty with a right footed shot to the bottom left corner.