The Baggies were beaten 4-3 in last night's third-round shoot-out at The Hawthorns - but only after Markus Rosenberg had missed a glorious chance to win the game late in extra time.
Reid said: "It's never nice to get beaten on penalties but I thought on the whole there were lots of decent performances.
"As has been the case a few times this season, we just lacked the cutting edge at times with the chances we had.
"We could have put it to bed a couple of minutes before the end of extra-time so we're a little bit disappointed. That's the difference between the top, top teams and the rest."