Manchester United boss Sir Alex Ferguson admitted his frustration after his side gave up a first-half lead to be held 2-2 by West Brom.
The Red Devils were two goals ahead at the break thanks to an early strike from summer signing Javier Hernandez followed by a Nani effort.
However, a Patrice Evra own goal paved the way for a Baggies fightback and Somen Tchoyi grabbed the equaliser to hold United to a stalemate.
Ferguson concedes he was disappointed by the result, insisting his side should have finished off their visitors with more goals while they had the advantage.
"The only criticism of the first half performance is that we didn't finish them off," Ferguson told MUTV. "It's very frustrating.
"It's not a defining result but we can't keep doing that. We were frustrated with that."
The United boss says he was happy with his side's first-half display, particularly the 'tremendous' goal from 'Chicharito'.
"I thought it was going very well," he added. "At the end Berbatov did well. They all did well. There are no complaints about the first-half performance.
"But if they're 2-0 down and you give them a goal, you're giving the other team a lifeline."
Ferguson did not comment on Wayne Rooney, who was omitted from the starting line-up and came off the bench for the final 20 minutes, but revealed Ryan Giggs has suffered a recurrence of a niggling hamstring injury.
"The loss of Ryan as a wide player was a big one for us," said Ferguson. "He has done his hamstring again.
"He got it against Bolton but he had trained all week and had been doing very well.
"But it has gone again and maybe we need to give him a longer recovery."