The Blaugrana trail leaders Atletico Madrid by three points going into the final round of the Primera Division season but the Catalans host the Rojiblancos at Camp Nou on Saturday night.
Given the two sides drew 0-0 at the Vicente Calderon earlier this season, Barca would take the title on account of a superior head-to-head record were they to defeat Diego Simeone's side.
"We have to win and we know Atletico are a very tough team to beat," Iniesta told reporters on Monday. "But la Liga is on the line and we'd have all taken this situation if we'd been offered it - a must-win game in the last match of the season, at home to the current leaders, Atletico. This team has never had that tension of going into the last game with the title at stake!
"And playing at home takes a lot of pressure off us and if we win I think it will be a bigger celebration than ever. If we go about it the right way, we'll win."
Some pundits have suggested that Barcelona do not deserve to retain their Primer Division crown, given how dramatically their form has dipped during the second half of the season, which has piled a huge amount of pressure on coach Tata Martino.
However, while Iniesta admits that the Blaugrana have endured a difficult and turbulent campaign, he insists that they would be worthy winners.
“Whoever wins will deserve it," the Spain international declared. "Why won’t we deserve it if we win? We’ve led the table, lost big games, won big games ... the league is about a whole season of effort but, right now, we will be putting a whole year’s work on a 90-minute game.
"Winning the league can’t cover up a poor season and if we do win it, that shouldn’t change anything about the future of the team.
“But whether we’ve done things right this season or not, this is our final. Winning the league would be a great way to sign off and it’d be great to win it for Tata and his people because of everything we have been through together. The first year at a club like Barca isn't easy."
With long-serving goalkeeper Victor Valdes and captain Carles Puyol already having confirmed that they will be leaving Camp Nou this summer, it has been claimed that this weekend's title-decider represents a perfect opportunity for Barca's current crop of players to bring the curtain down on an unprecedented spell of sustained success. However, Iniesta is reluctant to entertain such talk.
"I don't like speaking about the end of eras," the midfielder admitted. "Barca are about more than just the players who are here now. Players come and go, but Barca will always live on."
Barca's title-deciding clash with Atletico will kick off in Catalunya at 18:00CET.