The Republic of Ireland star has struck 11 times in as many matches since arriving in Glasgow on loan from Tottenham Hotspur while Hibs' once rock-solid defence has suddenly begun leaking goals at an alarming rate.
And while Anthony Stokes and Derek Riordan have claimed 35 goals between them, Hughes conceded it's the lack of clean sheets which have seen Hibs fall five points behind Dundee United in the battle to finish third in the SPL table.
Even although he watched his side score twice against United on Wednesday night, Stokes taking his tally for the season to 20, Hughes looked on in dismay as they shipped four at the other end.
It's a trait which he agreed simply cannot be allowed to continue if his side are to realise their faint hope of reeling in United over the final seven matches of the season while admitting Keane will give his defence another close examination. "Keane's always been a player I have admired, the way he can drop off, play on the shoulder, the way he goes and finishes," he said. "But for me any of my defenders knowing they will be up against him on Sunday should be inspired by the challenge of keeping him out."
Hughes agreed it would be a big test given recent events, saying: "We cannot concede the goals we have been losing and hope to win. I've always said we'll score goals and that's been happening but we need to start keeping that back door shut again."
Hughes insisted, however, that wasn't a criticism merely of his back four, adding: "When you say that everyone automatically thinks of the back line and goalkeeper, but it starts from the front. It's all very well trying to play expansive football, but when it breaks down everyone has to take responsibility."
While Hughes hopes to have Kevin McBride back from an ankle injury, he will be without Merouane Zemmama, Paul Hanlon, Alan Gow and Kevin McCann. David Wotherspoon, who twisted an ankle in training before the United match, remains doubtful.