Crucially, Alfa Romeo has struggled this season, with Raikkonen embarrassingly qualifying last at the recent 70th Anniversary Grand Prix at Silverstone, although the car improved for the Spanish GP last time out.
Assessing what is required for Raikkonen to remain with Alfa Romeo, Vasseur said: "I think the most important thing is the motivation, the motivation on the driver’s side first because I think it’s difficult for Kimi to struggle with the pace when we are at the back.
"Now that we did a good weekend in Barcelona, the pace was much better. We have to continue to improve and to do small step by small step and to be back into the fight.
"This is the most important thing but not just for Kimi, but everybody in the team. The main motivation in a racing team is coming from the results and nothing else, from the drivers to the mechanics, to the engineers, to myself and we need to get results."
Vasseur insists he has no issues with Raikkonen's performance so far this year which has failed to yield a point from the opening six races for the first time in his career.
Asked whether he was impressed with the job Raikkonen had done, Vasseur replied: "Yeah, yeah! Honestly, Kimi is far from being the biggest issue. He’s doing a good job.
"We saw in Barcelona that the pace is there. We have to continue to push and to get the last tenth [of a second] on every single topic and I think that Kimi is pleased when we have this kind of motivation."
GPFans is a multi-platform, multi-language brand dedicated to Formula One coverage. We bring you all the ins and outs of the sport, 24/7, everything from up-to-the-minute news and features to the latest viral stories and clips.
We believe that a new generation of exciting, outspoken drivers will make F1 more popular than ever before, and we want to give our users access to as much of their heroes as possible, on and off the track. From Lewis Hamilton to Max Verstappen, Daniel Ricciardo to Sebastian Vettel, we provide in-depth analysis of every every Grand Prix in the season, from Australia to Abu Dhabi.
With Formula One under the new ownership of Liberty Media, how the sport is being covered is evolving, and GPFans will look to be at the heart of this progression into new media, as one of the fastest-growing sites covering the king of motorsports.