Mixu Paatelainen says Dundee United must show a greater cutting edge after losing 1-0 to Hearts in the Finn's first game as manager.
Bottom-placed United were undone by Juanma's early penalty at Tannadice.
"What surprised me was that the quality let us down a little bit in the final third," Paatelainen told BBC Scotland.
"You've got to give credit to Hearts, how they defended, big, strong boys in there, but in the final third we were nowhere near as good as we should be."
United remain four points behind Partick Thistle, who defeated St Johnstone on Saturday, at the bottom of the Scottish Premiership.
And the new boss has had only had a few days of training with his players and says this is an area they will need to work on if they are to steer their way out of the relegation zone.
"We'll work on these things; it's very, very early days," he said. "We've not had a good chance to work on the offensive stuff; we wanted to make sure we defended well.
"I'm disappointed with the result but pleased with how the players tried and how committed they were."
Meanwhile, Hearts head coach Robbie Neilson says the win was a big psychological boost for the squad after being without a win in the league since August.
"There was a wee bit of pressure on the boys," Neilson admitted. "Now we've got that out the way, hopefully we can play Ross County at home next week with a bit more confidence if we take the lead.
"We're aiming for Aberdeen and today takes us within four points of them."
Neilson also said that striker Juanma must learn how the game is played in Scotland having gone down under a number of seemingly innocuous challenges from United defenders.
St Johnstone defender Brad McKay was fined by the Scottish Football Association after labelling the Spaniard a "typical foreigner" who "gets touched and goes down" following the team's meeting on the opening day of the season.
"In the continent, if there's contact, it's a free-kick," he said. "It's different here and he's still learning to play the game here.
"It's more physical. Defenders get away with a lot more here than they do in the continent.
"It's a learning process for him as well; he needs to realise he maybe needs to take a wee bit more physicality.
"There's times when he legitimately goes down and he doesn't get the free-kick - that's just part of football. He doesn't go down without a challenge."