Downing has said Sam Allardyce has stabilised the club and made some excellent signings.
Downing was signed by Allardyce from Liverpool at the start of last season, and this term has arguably been the best for the player at the Boleyn Ground - his form resembling more of the positive form he showed at Aston Villa rather than the struggles of his time at Anfield.
He said: “He has stabilised the club. He has made the squad better. Last summer was his best transfer window of getting players in to take us to the next level.
“I don’t think he gets the credit he deserves but if you look at his managerial record he has always had stability and always gets the best out of his players. For him and for us the best thing we can do is finish in a European spot.
“And I’d say that we were small details away from being a European team. If we didn’t so it this season it would be disappointing after being in fourth or fifth for such a long, long time. But we can do it.”
Allardyce did lead the side to promotion via the play-offs in 2012 and has consolidated their place in the Premier League - though last season wasn't the best given they were in the relegation zone at the midway point of the campaign.
This season looked promising with the likes of Enner Valencia and Diafra Sakho coming into the club to provide pace and high pressing in the final third, while Alex Song looked to bring a quality, experienced presence in central midfield.
But the side has lost its way this season, having not won a league game since their 3-0 victory over Hull City in January, which now leaves them in danger of dropping out of the top 10, after Allardyce had repeatedly stated that he would like to bring European football to West Ham.
With Allardyce's contract up in the summer, and rumours starting to circulate over both his position and links to other clubs, this run of form has come at the wrong time and he needs a strong finish to the season with nine games remaining.