Downing scored in last month's 3-1 Premier League triumph at Crystal Palace and had a hand in both goals as West Ham drew 2-2 at Hull City on Monday.
The 30-year-old will line up against his former club Liverpool on Saturday and his manager revealed what a pleasure he has been to work with at Upton Park.
Allardyce told the club's official website: "He's never an ounce of trouble, gets on with his job...as a pro and as a lad who just wants to come in and do well, from my point of view it's just fantastic.
"He's been a terrific player in his time and he's still got a lot of years left in him. And he'll be enjoying playing with the players he's playing with.
"Everybody has accepted in our squad that they have to get matched up to the extra ability that we've got and hopefully that will get us more results."
Allardyce has taken four points from as many games this season, leaving West Ham 13th in the table.
