Ospreys head coach Steve Tandy was left to rue a handful of mistakes from his team as they went down 24-16 to Edinburgh at Myreside on Friday.
The defeat was their fourth of the Guinness PRO12 campaign and means they could well relinquish top spot after the weekend is concluded on Sunday.
And for head coach Tandy it was a showing that left a lot to be desired, as he admitted his disappointment after the full-time whistle in Scotland.
"We are pretty frustrated," he told the Ospreys website.
"If I'm honest, I'm disappointed. We coughed up the ball far too many times, too many basic errors, and the minute we got into opposition territory, get some field position, we spooned the ball and coughed it up. It's a bitterly disappointing night for us.
"I think we played some good stuff in the first-half, had a couple of opportunities, and at this level when you come away from home you need to take those. You can't expect to win games when you stack up as many errors as we did tonight. It's as simple as that."
He added on their injuries and Test absentees: "This is a tough block for us but it's something that we were pretty excited about coming into it. I think that makes this harder to take, as we are bitterly disappointed about the performance.
"With the injuries we've got, and the international call-ups, it does ask more of our young kids, and on the whole we are pretty pleased with them. It's just tonight we weren’t good enough.
"It's going to be another tough encounter next week, and the reality is that if we play like this against Glasgow we'll find ourselves on the end of a pretty harsh scoreline. We've already highlighted how important this period of the season is for us, and these boys have to take responsibility. It's not just about the youngsters, there has to be the guidance from the experienced ones, who've been there and done it, to help steer them through. That's important for us at the moment.
"We'll review the game over the next 48 hours, take a good look at the analysis, and then on Monday morning we'll get back on the horse and look how we can work our way through this."