A victory in the derby against Real Betis on Saturday will take Sampaoli's side above Madrid by virtue of their superior head-to-head record, although the European champions will have two games in hand.
Sampaoli acknowledges that Madrid's surprise 2-1 loss to Valencia on Wednesday has given Sevilla and reigning champions Barca added hope in the title race, but he has warned his players not to allow their standards to slip in the same way when they meet Betis at the Benito Villamarin.
"We have mentally prepared to go for the win and that will lift us up to the top of the table," he told a news conference. "If we win such a difficult match at this stage of the season, we will have achieved our objective, one that would allow us to dream.
"We didn't have the week to prepare for the most important game of the year. We played a very good game in the Champions League and we are trying to put Sevilla up amongst the top eight teams in the world.
"We are also aware of happened to Real Madrid in Valencia, and now today we have the possibility, the chance to realise our dream.
"This week is fundamental. We have dreams just like everyone else in football and of course we dream about going top, but we go into this game knowing it's going to be a difficult one and we face a very complex scenario because Real Betis are very strong at home, they raise their game against teams there and especially against us.
"But this is a unique chance to win and keep the dream alive. Our moment is now."