The Foxes edged Villa 1-0 at King Power Stadium on Saturday which made it three wins in their past four outings in all competitions.
The result followed up the 1-0 home triumph over Newcastle United in the third round of the FA Cup on January 3, giving Nigel Pearson's side a third clean sheet in four fixtures, and gave right-back Simpson plenty of confidence ahead of next weekend's clash with Stoke City.
"I think the key for us for the rest of the season is to try and keep as many clean sheets as possible and keep it tight at the back," he told the club's official website.
"It's a massive win. It's been a good couple of weeks for us. You want to keep that momentum going. Villa are in and around us at the moment so it's a massive three points and helps us keep in touch with the rest of the pack.
"It was a tough 13 games but we knew we were close. We knew we had to keep doing the right things and we still are.
"It's been a good few weeks for us and we need to keep that going now."
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