Plymouth Argyle boss Ryan Lowe has hailed the impact of newly-signed striker Niall Ennis.
"He was outstanding, you can put your trust in him anywhere," Lowe said.
"His aggressiveness, his hold up play, his running with the ball, his mentality, he's been on another level since he's come in to be fair to him."
"I don't like singling anyone out but he's been different class," added Lowe of Ennis, who spent last season on loan at Doncaster and has also had spells at Shrewsbury Town and Burton Albion.
But Lowe was less pleased with the way his side defended as they gave away a goal early in either half to lose 2-1 at the Keepmoat Stadium to drop to 14th in League One.
"Two moments of sloppiness have cost us," Lowe added.
"The first one, not picking your man up from a corner and the second one, not picking your man up from a second phase from a corner.
"We went two months without conceding at a set-play and now we've conceded two from second phases and one from a corner and that can't happen.
"I don't like singling anyone out or naming any players, but they know who they are and they've got to do better because when you're tagged with a man we've got to put that trust in you to make sure that he doesn't score.
"Today, two players have let us down from first phase and second phase set-plays."