Morecambe boss Jim Bentley says they must improve their game management after their 94th-minute EFL Cup defeat by Championship side Barnsley.
Barnsley had taken a 3-1 lead just after half-time in the first-round tie on Tuesday, but Morecambe fought back.
Michael Rose scored from the spot and Vadaine Oliver levelled but Ryan Hedges scored a late winner for the Tykes.
"I am absolutely gutted with the manner in which we were beaten," Bentley told BBC Radio Lancashire.
"We got back to 3-3 all and you're thinking 'right, it's going to be us here'. My disappointment is our game management."
The defeat came just three days after Morecambe were on the other end of a late goal as Garry Thompson's 91st-minute volley gave them an opening-day win at home to Cheltenham Town in League Two.
Bentley continued: "We knew that Barnsley posed a threat but you go from one extreme when on Saturday you win in the last kick of the game and being overjoyed, to losing in the 94th minute.
"In the space of a couple of days we've been on the wrong end of it. I was very disappointed but there's plenty to be positive about."