Ole Gunnar Solskjaer bemoaned Manchester United's second penalty miss of the week as his side fell to a shock 2-1 defeat to Crystal Palace.
But the United boss was also unhappy the hosts weren't awarded another spot-kick before Patrick van Aanholt's late winner.
Having been held to a draw at Wolves on Monday when Paul Pogba failed to convert, Marcus Rashford's second-half spot-kick hit the inside of the post before Palace claimed their first Premier League win over United.
"Two games, two missed penalties," rued Solskjaer. "If you score them, it's a different scenario."
To add to Solskjaer's irritation, he also believed United were unfortunate not to be awarded another penalty in the second half when Rashford was seemingly felled in the box.
On a day of frustration at Old Trafford, Palace scored with two of their three shots on target.
"We just weren't clinical enough. They scored two very easy goals. We created enough to win the game. But we didn't defend well enough," said Solskjaer.
"We dominated the game but we didn't control it. We should have dealt better with the last five minutes.
While Victor Lindelof was at fault for Palace's opener, scored by Jordan Ayew in a rare breakaway attack, goalkeeper David de Gea was to blame deep into injury time when he couldn't repel Patrick van Aanholt's near-post shot.
"He's disappointed," said the United boss. "But he's disappointed every time he concedes a goal."
Speaking to United's official website, Solskjaer added: "The last two results were disappointments because at Wolverhampton you feel we deserved to win, and today we deserved to win, but you don't always get what you deserve in football. We have to make sure we go to Southampton with the bit between our teeth and play better, score goals and win the game.
"The first half was poor. In the first half-an-hour you're feeling you're controlling it and maybe it seems too easy. We didn't really have that zip and urgency about us and they scored with the first chance. Just a long kick, it should never happen, that's poor defending. But in the second half, I thought we were excellent. We were pressing, pushing, creating chances, just not scoring."