The 23-year-old has four goals in 10 appearances already this season, and Ranieri will be hoping he can carry his form into Watford’s trip to Arsenal on Sunday.
Sarr had joined Watford for their last Premier League campaign for a club-record fee in the summer of 2019 but struggled in a tumultuous season for the club, finishing with just six goals.
The following Championship season however, the 23-year-old finished with 13 goals to his name and has impressed on his top-flight return.
“For me he is a diamond. He is a diamond and I have to work with him in every direction. I think he can achieve very big things,” the Hornets manager said.
“When I worked in France I was told there are so many diamonds there but it is important to work with the general football philosophy that is in Europe.”
“Ismaila is one of the players who can decide – in any moment – the match,” he added.
“I don’t want to give him more motivation, he’s young I don’t want to put too much pressure on him.
“He has to play how he is used to playing, after the match I will speak with him.”
Since Ranieri took over, Watford shipped five goals at home to Liverpool only to score five themselves in his second game at Everton the following weekend.
The third game was a less eventful single-goal defeat to Southampton, but it leaves Watford without a home win since their opening game of the season and just three points above the relegation zone.
They travel to the Emirates for Ranieri’s fourth game in charge, ahead of yet another international break, and the Italian highlighted the importance of playing well ahead of the gap in fixtures.
“Of course for us it’s very important to have a very good performance. The result could be positive or negative but the performance must be very, very high very strong.
“I believe in our performance on Sunday.”
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