The Manchester City goalkeeper clashed with Brentford star Ethan Pinnock during the 3-1 win at the Gtech Community Stadium.
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Onana, 27, has twice this season made rash decisions in the box, both of which came against Wolves.
The Cameroonian clattered into players when trying to get to the ball, but managed to avoid punishment on both occasions.
On Monday it was the turn of Ederson who charged off his line and wiped out Pinnock in the process.
But as the incident occurred outside of the box VAR could not intervene after referee Jarred Gillet waved play on.
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Smith was on commentary for Sky Sports and suggested the Brazilian’s challenge was “Onana like”.
And Manchester United fans were less than impressed by the former Arsenal man’s sly dig.
One posted: “Ederson just absolutely wiped out Pinnock. The Sky commentator just said ‘that’s Onana like’ what is that.”
A second wrote: “How’s Onana catching strays from the comments.”
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A third commented: “Andre Onana seeing Ederson flying into someone for no reason and not getting punished for it.”
A fourth said: “Onana always disgracing us.”
Another added: “It literally is though Onana done it twice.”
Onana has struggled to show his best form since his arrival at Old Trafford from Inter Milan last summer.
The goalkeeper has endured a number of high-profile blunders including the two against Wolves.
In September he made an error leading to a goal against Bayern Munich as United lost 4-3 at at the Allianz Arena.
That was followed up by a dreadful error against Galatasaray which saw a penalty given away due to a bad bit of distribution.
Against Brentford, Onana let a tame shot squirm underneath him, and in the reverse fixture against Galatasaray, he let in two savable free-kicks from Hakim Ziyech.
Despite the number of errors, in December Erik ten Hag claimed that Onana was the second-best keeper in the Premier League.
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