Damon Hill says Stoffel Vandoorne has yet to make an impact in Formula 1, suggesting the McLaren driver should perhaps shed his "nice boy" image and race harder.
Vandoorne is in his second full season of F1 and has scored in three out of the five races so far in 2018, enduring his first retirement of the year in Sunday's Spanish Grand Prix.
The 26-year-old's performance has lagged expectations however, but he's also up against tough opposition at the Woking-based outfit, with Fernando Alonso sitting on the other side of the garage.
The Spaniard has consistently had the upper hand over his team mate, leading some to believe that, while talented, Vandoorne may just lack the edge necessary to take him to the next level.
"I've known Stoffel since the beginning. He was in the same category as my son and I always admired his talent," Hill told Belgian broadcaster RTBF.
"He has a lot of potential. But in Formula 1, to be successful, you need something absolutely incredible, and with him we haven't seen that yet.
"He hasn't yet managed to get people to say 'Wow'. I think he has to let go a little, get rid of the 'nice boy' side and maybe become a little meaner," Hill smiled.
The Belgian's contract with McLaren runs out at the end of 2018. He insists he isn't considering alternative options for next year, but with McLaren junior Lando Norris lurking in the wings, circumstances may decide his fate.
"I do not look at any other option except McLaren," he told Spain's El Pais.
"I have a very good relationship with the company, I occupy a very important position and I think the team has a very high potential for the future."
Assessing his performance this year, Vandoorne believes he's racing almost on a par with Fernando Alonso.
"I don't think there is much between Fernando and I," he said.
"Fernando is one of the most complete drivers on the grid in terms of getting everything from the car he drives, but we are not as far apart as it may sometimes appear."