Chris Hughton was baffled that the Video Assistant Referee was not consulted after Brighton were denied a penalty during the FA Cup fourth-round stalemate with West Brom.
Seagulls boss Hughton felt striker Jurgen Locadia was fouled inside the box by Baggies defender Kyle Bartley as he followed up Dale Stephens' second-half shot against the left post.
VAR was available for the 0-0 draw at the Amex Stadium but referee Lee Mason opted not to use the technology for the 58th-minute incident.
"On a day where we were picked as a VAR game and incidents that should be picked out, we saw it on the side and even if the referee hasn't seen it, Locadia has gone down in the box," said Hughton.
"The fact that he's gone down in the box, then that's one that should be picked up.
"We've seen it again, it looks like a penalty."
Brighton had 24 attempts on goal on Saturday but were unable to break down their dogged Sky Bet Championship opponents as they were forced to settle for a replay at The Hawthorns.
Stephens' attempt, which was touched on to the upright by Baggies goalkeeper Jonathan Bond, was as close as they came, while defender Tosin Adarabioyo later headed against the crossbar for the visitors.
Hughton, who is prioritising Premier League survival and admitted a rematch next month is not ideal, had no complaints about the result after making six changes to his starting XI.
"On the balance of play, I felt we were the better side. But we couldn't find that way (through)," added Hughton.
"We didn't do enough to win the game, we didn't test the goalkeeper enough to win the game.
"Credit to West Brom, they probably feel they deserved to get the result they did."
There will no replays in the competition from the fifth round, with drawn matches settled on the day with extra-time and, if necessary, penalties.
Asked about the prospect of a midweek trip to the West Midlands, Hughton added: "I'm not one to want to mess around with what the rules are.
"I do think in the latter stages it should be finished on the day. But this is a cup competition that everyone wants to stay in."
Promotion-chasing West Brom retained just two players from Monday's Championship win at Bolton as they fielded an inexperienced team, with seven academy products in their squad.
Baggies boss Darren Moore was impressed with the display of his youthful line-up.
"I thought it was a good cup match. It was two teams trying to win it and both teams just couldn't break the deadlock in the end," he said
"I thought on the ball some of those younger players displayed talent and ability against a good opposition, which caused them some problems. I'm very pleased."
West Brom are four points outside the top two in the second tier with a game in hand after promotion rivals Norwich and Sheffield United drew on Saturday, while leaders Leeds won at Rotherham.
Moore does not view the additional fixture against Brighton as a negative in the club's quest for an immediate return to the top-flight.
"It's not a hindrance because there's huge admiration for the FA Cup here at West Bromwich Albion Football Club," he added.
