The on-loan Fleetwood Town striker picked up the accolade after a string of impressive performances for the Ton.
"I'm delighted. To be picked ahead of Hibs or Rangers players who have played so well is a big thing," he said.
The 21-year old has been used in a more advanced midfield role this season to accommodate team-mate Denny Johnstone up front for the Greenock club.
McManus is in his second loan spell at Cappielow. Following last season's League One success, he admits things are a lot more difficult at Championship level.
"I've only been back here since January but I'm enjoying every minute," he continued.
"We've been getting good results and teams like Rangers and Hibs haven't found it easy against us.
"There are better players in this league, better teams.
"I've played more of an attacking midfield role this season and I've tried to fill in for the team more so the gaffer's happy with me.
"I've still got a few goals and a few assists so I'm happy all round. I hope now to just keep it up."
Last month McManus scored once against Alloa in a 2-2 draw and a brace in a 3-2 defeat by Raith Rovers, both matches away from home.

Antoinette McKeown was suspended on full pay in March 2015 and dismissed last November on the recommendation of an independent disciplinary panel.
However, an independent appeals panel has overturned the ruling.
It said it found flaws with the previous disciplinary process.
Ms McKeown had been appointed as the head of Sport NI - the body charged with encouraging participation in sport - in June 2013.

The North Shields-based Homeland prawn boat was in collision with the Scottish Viking off the Berwickshire coast just before 2000 BST on Thursday.
Two fishermen, who are brothers, were on board the trawler. One, aged 20, was pulled to safety by another boat.
The search for the other brother, thought to be 16, has been called off.
Fred Caygill from the Maritime and Coastguard Agency (MCA) told the BBC a crewman from another vessel had seen the missing boy in the water at 2025 BST on Thursday, but he then slipped from view.
The MCA confirmed the search was terminated at 1400 BST on Friday, a decision which had followed 17 hours of searching, when expected survivability had been exceeded.
Mr Caygill said it was unclear as to whether the missing boy, or his brother, were wearing lifejackets, but two were found in the flotsam.
He said: "The survivability period for someone in the water has passed.
"Different factors affect different people's chances of survival, but it has been a long time."
More than 20 fishing vessels and lifeboats were involved in the search, which spanned an area of more than 30 square miles off St Abb's Head.
The Scottish Viking ferry, which was travelling between Rosyth and Zeebrugge, is operated by the Dutch company Norfolkline, owned by DFDS Seaways.
The firm said the ship was chartered by Norfolkline from Italian firm Visentini, and was expected to arrive in Belgium on Friday afternoon.
A DFDS Seaways spokesman said: "We are deeply concerned about this and there will now follow an investigation by the authorities which we will fully assist with.
"We have also been talking to Visentini who will investigate fully."
The Marine Accident Investigation Branch will examine how the collision happened.
A spokesman said: "We are conducting a preliminary examination at the moment."
Lothian and Borders Police said officers were assisting the coastguard.
Morton's Declan McManus has won the Ladbrokes Championship player of the month award for February.
[NEXT_CONCEPT]
BBC Sport NI understands that an independent appeals panel has overturned the charges of gross misconduct against the former chief executive of Sport NI.
[NEXT_CONCEPT]
An investigation is under way into a collision between a ferry and a trawler which has left a teenage fisherman lost in the North Sea.