With the club's current three top scorers all injured, Benitez is looking to his new signing to bridge the gap.
"We were looking for someone to give us a lift and that's why we went for Maxi," said the boss.
"He knows Javier Mascherano and Fernando Torres and the big positive from that point was they have a very good opinion of him. He is a player who knows about the game.
"He also uses the ball well and can finish - he has scored a lot of goals in his career, has a very good record and now we want him to do the same for us.
"Normally if you can keep the ball, he will be there. He likes to get into the box and has a record of up to 15 goals every year.
"We have had some players playing too many games and we needed to give these players a rest. If we can choose Maxi, then give someone a rest, it will be really good for the team."