Derby County have become the latest Championship casualties of the League Cup first round, having fallen to a 2-1 defeat at the hands of League Two side Portsmouth.

Pompey began their league season with a comfortable victory at the weekend, and that confidence spilled over into the opening stages of this match as they made the brighter start to the encounter.

However, efforts from Adam McGurk and Kyle Bennett failed to trouble Lee Grant in the Derby goal, and it was the Rams who had the first real chance when Andreas Weimann saw his effort blocked.

The hosts continued to fire warning shots, though, with Brandon Haunstrup and Bennett again coming close to grabbing a shock opener for Paul Cook's men.

It was Derby who ended the half on the front foot, however, as Jeff Hendrick exchanged passes with Simon Dawkins before firing an effort towards goal that bobbled narrowly wide of the upright.

They were unable to pick up where they left off at the start of the second half, though, as Portsmouth opened the scoring just four minutes after the restart when McGurk connected with Jayden Stockley's cross to squeeze his header past Grant.

Far from sitting on their lead, Pompey went in search of a second goal and it took a double save from Grant to deny them it as both Stockley and Ben Davies were denied in quick succession.

The second goal of the game did eventually arrive, but it went to the visitors as Jason Shackell opened his Derby account with a firm header home from Johnny Russell's corner.

Parity lasted only three minutes, however, as teenager Conor Chaplin drilled a smart finish into the bottom corner just five minutes after being introduced as a sub.

Derby pushed for an equaliser and almost got it through Chris Martin late on when the striker turned and shot inside the box, but his effort flew just wide as the hosts held out for a famous victory.