text: The Mariners, back in League Two after a six-year absence, looked nervy early on and former England striker Darren Bent twice went close for the Rams.
  Derby made the breakthrough when captain Keogh stooped at the far post to head home Craig Bryson's cross.
  Shaun Pearson saw his header saved for Grimsby and Kayden Jackson's shot was cleared off the line in injury time.
  Match ends, Derby County 1, Grimsby Town 0.
  Second Half ends, Derby County 1, Grimsby Town 0.
  Corner,  Grimsby Town. Conceded by Alex Pearce.
  Attempt saved. James McKeown (Grimsby Town) header from the centre of the box is saved in the top centre of the goal.
  Corner,  Grimsby Town. Conceded by Richard Keogh.
  Attempt saved. Shaun Pearson (Grimsby Town) right footed shot from the centre of the box is saved in the top centre of the goal.
  Corner,  Grimsby Town. Conceded by Alex Pearce.
  Corner,  Grimsby Town. Conceded by Richard Keogh.
  Attempt missed. Cyrus Christie (Derby County) left footed shot from outside the box misses to the left.
  Attempt missed. Jacob Butterfield (Derby County) right footed shot from the left side of the box is close, but misses the top left corner.
  Substitution, Derby County. Jeff Hendrick replaces Will Hughes.
  Substitution, Grimsby Town. Tom Bolarinwa replaces Ashley Chambers.
  Attempt missed. Tom Ince (Derby County) right footed shot from the left side of the box is close, but misses the top right corner.
  Substitution, Grimsby Town. Kayden Jackson replaces Dominic Vose.
  Attempt missed. Darren Bent (Derby County) header from the centre of the box is just a bit too high.
  Substitution, Derby County. Tom Ince replaces Nick Blackman.
  Substitution, Derby County. Jacob Butterfield replaces Chris Martin.
  Corner,  Derby County. Conceded by Andrew Boyce.
  Corner,  Grimsby Town. Conceded by Alex Pearce.
  Goal!  Derby County 1, Grimsby Town 0. Richard Keogh (Derby County) header from the left side of the six yard box to the top left corner. Assisted by Cyrus Christie following a set piece situation.
  Attempt missed. Will Hughes (Derby County) right footed shot from outside the box misses to the left.
  Corner,  Derby County. Conceded by Shaun Pearson.
  Substitution, Grimsby Town. Rhys Browne replaces Sean McAllister.
  Attempt missed. Nick Blackman (Derby County) right footed shot from outside the box misses to the left.
  Attempt missed. Craig Bryson (Derby County) header from the centre of the box misses to the right.
  Corner,  Derby County. Conceded by James McKeown.
  Attempt saved. Johnny Russell (Derby County) right footed shot from outside the box is saved in the top left corner.
  Corner,  Derby County. Conceded by Ben Davies.
  Attempt missed. Darren Bent (Derby County) header from the centre of the box misses to the right.
  Second Half begins Derby County 0, Grimsby Town 0.
  First Half ends, Derby County 0, Grimsby Town 0.
  Attempt missed. Alex Pearce (Derby County) header from outside the box is close, but misses the top right corner.
  Corner,  Derby County. Conceded by Shaun Pearson.
  Corner,  Derby County. Conceded by James McKeown.
  Attempt saved. Nick Blackman (Derby County) right footed shot from outside the box is saved in the bottom left corner.
  Attempt missed. Nick Blackman (Derby County) right footed shot from outside the box is high and wide to the right.
  Attempt saved. James Berrett (Grimsby Town) right footed shot from outside the box is saved in the top centre of the goal.
  Attempt saved. Will Hughes (Derby County) right footed shot from outside the box is saved in the top centre of the goal.
  Attempt saved. Craig Forsyth (Derby County) header from the left side of the box is saved in the top centre of the goal.
  Attempt missed. Johnny Russell (Derby County) right footed shot from the right side of the six yard box misses to the right.
target: Richard Keogh's second-half header edged Derby into the EFL Cup second round with victory over Grimsby.