Auckland City striker Sanni Issa is their main attacking threat and has scored 16 goals this season.
Mangere had a favourable Cup draw to reach the quarter-finals, beating Waikato Unicol, Te Puke United, Waitemata AET and Papakura City. But they turned heads in Otago, knocking over Football South heavyweights Dunedin Technical in difficult conditions.
"We didn't want to draw Eastern Suburbs because we have been monitoring their performances and we know they are a really good side, but now that we have got them - we just have to play," said Hassan.
Eastern Suburbs are enjoying their most successful season since the 1960s, during which they became Northern League champions twice and lifted the ASB Chatham Cup on three occasions. They claimed a league and cup double in 1965 and, after securing the NRFL Premier League title last weekend, are looking to repeat that feat for only the second time in their history.
"I don't think there are many players that need motivating for the semi-final of the cup," said Suburbs coach Malcolm McPherson. "It's been a big six weeks for us. We've played some really good sides along the way and I think the boys are pretty much used to the big games now. This is another one for us to look forward to."
On Sunday, Central League champions Napier City Rovers travel to Shepherds Park to take on Birkenhead United AFC in the second semi-final. Rovers are looking to earn their seventh ASB Chatham Cup Final appearance while Birkenhead will be hoping national league recruits Danny Robinson, Chad Coombes and Adam Dickinson can help them make their first final.
"We've got big junior numbers and we've got everybody to try and get involved to make it a really good day out," said Birkenhead coach Paul Hobson. "We want to accommodate everybody and give a really good account of our club for the day. Days like this bring clubs together so it's going to be fantastic."
Birkenhead have conceded just once in four cup games on their run to the semi-final - a record which includes dates with former ASB Chatham Cup winners, and fellow NRFL Premier League clubs, East Coast Bays and Central United.
Eastern Suburbs AFC v Mangere Utd
Saturday 29 August, 2pm
Madills Farm Recreation Reserve, Kohimarama
#EASvMAN
Birkenhead United AFC v Napier City Rovers
Sunday 30 August, 1pm
Shepherds Park, Birkenhead
#BIRvNCR