Plymouth boss Carl Fletcher said his side lacked quality on the ball during their 1-0 defeat at Rotherham.
The game was settled by a 73rd minute strike from substitute Kieran Agard after the Millers dominated for long periods.
"We defended well and never gave up but we just lacked a little bit of quality on the day," said Fletcher. "We could have had a couple of goals, but in possession today we just weren't at it.
"We knew we were going to come under pressure from set pieces and we had a game plan and it worked well, but we had lads marking players a lot bigger than them and they stuck at their task really well.
"We just had no quality up front. Whether it was a short pass or a long pass we just didn't have that quality and usually that's a good 'un for us.