Dundee manager Barry Smith insists his side will improve after another fruitless outing in the derby defeat by Dundee United at Tannadice.
followed a home defeat at the hands of St Mirren last week and Smith's men have yet to score in the Scottish Premier League this season.
"We will progress throughout the season and we still feel there's more to come from our boys," said Smith.
"Defensively, we're making mistakes that are costing us."
The visitors made a decent start to the first competitive Dundee derby in seven years, with Nicky Riley denied twice in quick succession by United goalkeeper Radoslaw Cierzniak.
But Gavin Gunning's 14th-minute opener and two goals in three minutes by Johnny Russell gave the hosts an unassailable lead.
"We started the game well, had a great chance early on," added Smith.
"Nicky's been out for three or for weeks and isn't as sharp as what we would like him to be, but we need to start converting those chances, especially as good a chance as that.
"It doesn't matter what level you're at, you can't defend like that. You look at how clinical United were.
"But it's disappointing the goals we're conceding just now and it's something that we'll definitely need to sort out because it's not good enough."