With just one point separating Newcastle and the bottom three, Slimani will be well aware that he must hit the ground running if he is to save his and his new club's season.
"Clark is training - he had a knee problem", said Benitez. Sanchez is exactly the type of player who can make a difference through individual brilliance against a side like Newcastle United who are expected to be cautious and well drilled at the back and it will be interesting to see if the 29-year old can deliver the goods for the Portuguese and help him break the St. James Park hoodoo at the weekend.
"So, I think the natural outcome is that he will have his [new] contract and he will be a Manchester United player for years".
"I know that some people did not like the substitution last weekend, but when Palace were attacking and attacking, the intensity was high".
Newcastle would surely settle for yet another 1-1 draw today against Manchester United, as Kenedy gets an opportunity to face the manager who gave him his debut in England back in the season we shall not talk about at Stamford Bridge. We scored a goal and we were quite well organised, and then we made a couple of mistakes and we conceded two goals.
"I like the feeling of going to Mr [Sir Bobby] Robson's home, I like the Geordies and the stadium but I have lost and drawn a few times there".
Newcastle have not won at home in the league since October and this fixture is not exactly helpful when it comes to them trying to improve on that poor run at St James' Park.
Alexis Sanchez breaks records following Man Utd transfer
Sanchez had always been expected to join Premier League leaders Manchester City as his Arsenal contract ran down. The Chilean has been found guilty of tax fraud committed during his time with former club Barcelona .
Newcastle have won just twice in 28 Premier League meetings, most recently at home in 2012 (D7, L19).
Manchester United are in second place in the Premier League table but 13 points behind runaway leaders Manchester City.
They are only one point better off than at this stage in the 2015-16 season, which ended in relegation.
Manchester United have kept clean sheets in five of their last six Premier League games. However, that defeat came in their last away game at Tottenham.
However, Sanchez has played four Premier League games against Newcastle without scoring.
Slimani is confident his new side can turn the tide by extending Mourinho's six-game winless run in the league on Tyneside.