Manager Ian Baraclough was delighted to win on his home debut as Motherwell boss but wants his team to have more self-confidence.
John Sutton tucked away an early penalty to make it two wins from two for the former Sligo Rovers boss.
"That's two wins and two clean sheets now and that's something to build on," he told BBC Scotland.
"The commitment and endeavour cannot be questioned but we are giving the ball away too easily. The players are better than that. They need to believe in themselves and try to relax and pick the right moments to go and play."
Motherwell dominated the first half but fell away after the break and were hanging on to ensure maximum points.
"I think we deserved to win over the 90 minutes but that second half was tough watching," added Baraclough.
"Partick Thistle threw a good bit at us and we didn't help ourselves. I'm a bit annoyed we didn't use the ball better.
"We went deeper and deeper to protect what we had, we couldn't get about them. So that could be better.
"First half, people wanted to get on the ball and we made angles for each other; that was the difference. We created some really good chances and we had the momentum. I think our play merited further goals."
The Motherwell penalty was awarded when Stuart Bannigan impeded Lionel Ainsworth and Partick Thistle manager Alan Archibald was unsure if the offence had taken place in the box.
"I think it's a foul, the only area we are questioning is whether the first touch is outside," he told BBC Scotland. "Stuart thought that as well. He was caught wrong side and gave him a tug.
"We had the better of the second half and pushed Motherwell all the way to the very end.
"We didn't have enough clear-cut chances and that's disappointing. That's down to the wrong choices from our players and some very good defending.
"They were throwing their bodies on the line to make blocks."