Saints extended their lead at the top of the JD Cymru Premier to 11 points with Saturday’s 3-1 home victory over Haverfordwest County.
They remain unbeaten in the league this season with a record of 17 wins and three draws from 20 matches.
Flint, tonight’s hosts, are currently ninth in the table and picked up a point from their last game, a 1-1 draw at home to Aberystwyth Town on Friday night.
“Every game, especially away from home, is tough,” said McManus. “Flint will make it tough, as they always do when we go there.
“It’s a chance for us to go and put another stamp on it and get another three points and kick on from there.”
McManus has enjoyed an impressive return from injury by coming off the bench as a substitute to score in the last two TNS matches.
After netting the winner in last Tuesday’s 1-0 victory at Caernarfon Town, the Scottish striker completed the scoring against Haverfordwest.
“Yes, I feel good,” he said. “Obviously, I’m just catching up and that will come with game time.
“Match fitness is the hardest thing to get, so once I hopefully get back in the team through starting games again, I’ll get up to speed as quick as possible.”
Reflecting on Saturday’s latest victory, as Saints added three more points to their total at the top of the table, McManus added: “I think it was a carbon copy of the game down at Haverfordwest.
“In spells we had loads of chances, we never took them.
“We gave them a chance and they took it and got themselves back in the game.
“At 2-0 if you’ve got plenty of chances, a third will usually kill the game and we never quite got that.
“We let them back into it and they put us under a bit of pressure, but thankfully I managed to grab the third and seal the three points.”