The Well captain reckons the current uncertainty at United, who will lose manager Peter Houston in the summer, could inspire the Tangerines to greater things between now and the campaign's end.
And while Motherwell are unbeaten against United in the league this season, Lasley expects nothing less than a hard-fought encounter.
"They know that the manager is going at the end of the season and that can work in their favour," he said. "You might find that they are bursting a gut to impress whoever might be coming in."
Motherwell have impressed this season after their admirable efforts in finishing third last term, but with suspensions and injuries bound to hamper them at some stage, Lasley knows the importance of racking up points while the going is good.
"We can be quietly satisfied with how we have done up until this point, but the months that are coming up are always quite intense," he explained. "If you end up with a couple of key players out because of knocks or suspensions then you can start to drift a little bit.
"We have a look at the other results as soon as we come in from our own game to check where everyone is. There is so little between the teams, Celtic apart, and you know that one or two poor results – either for yourself or those around you – can change the picture dramatically.
"There is a real chance to finish in second place, which would be worth a lot financially to the club but also professionally to the players."