Earlier this month, Sweden suffered defeats in close encounters against Poland (74-72) and Iceland (73-70) before being well beaten by Portugal last weekend, 78-61.
But those matches were played without Larsson - the Miami Heat man joined up with the squad earlier this week - and his deployment was sure to add an extra dimension to Mikko Riipinen's side.
Against fellow-EuroBasket qualifiers Estonia, though, Sweden would face another tough test, and so it proved after the first quarter ended 21-21.
The visitors then began to pull clear in the second, opening up a 10-point lead before ultimately taking an eight-point advantage at the half, 44-36.
In front of a large home crowd, Sweden rallied in the third quarter and put together a 12-4 run that helped them go 63-61 ahead, only for all their hard work to be undone as Estonia took the final eight points of the quarter.
Estonia still led by six in the final three minutes, before another excellent run by the home side edged them back in front, 87-85, in the last minute, only for Artur Konontsuk to respond with a three-pointer for Estonia.
With their final possession, Sweden turned to Larsson with his Miami coach Erik Spoelstra watching on from the front row. The 24-year-old drove to the basket, only for his shot to take a spin around the rim and drop out, handing the visitors an 88-87 win.
After the match, the shooting guard said Sweden had "many bad minutes" but "a few good ones that keep us in the game."
Larsson was pleased with his side's mentality, despite another loss, "We still showed the right fighting spirit and attitude in the end, so that we came back."
On 27th August, Sweden will end their 12-year wait to return to EuroBasket, when they begin their Group B campaign.
The Blagult's group stage matches will all be played at the Nokia Arena in Tampere, Finland, and they will need a top-four finish in what looks to be a tough six-team group to progress to the knockout stages.
They begin with a local derby against Finland, then the small matter of a meeting with world champions Germany two days later. Great Britain, Montenegro and Lithuania complete Sweden's schedule.
Click here for the full EuroBasket schedule and follow the tournament on Flashscore.
