The latter pair have made little or no contribution to City’s run to the top of the table after seven rounds but Metcalfe, who has just turned 20, has been ever present until missing the stirring 3-2 win over Western Sydney last week because of an injury he sustained on Olyroo duty.
Mombaerts’ team have been the entertainers so far this season, scoring a league-high 16 goals at an average of more than two a game.
Jamie Maclaren has been in scintillating form, scoring nine so far in just a handful of games, having missed fixtures because of injury and because he was on international duty.
But they have been slack defensively, conceding 11 goals: only struggling Melbourne Victory, second from bottom on the table, have let in the same, while every other club in the league, even cellar dwellers Wellington, have conceded fewer.
That, Mombaerts admits, is a concern.
He is delighted with the way his players fight and have shown the mental strength to come back from disappointing losses and heavy defeats like the 4-3 reverse in Brisbane when they were twice two goals ahead and the 4-0 FFA Cup final shellacking in Adelaide.
But he wants them to shore up the holes in their leaky rearguard.
“I am very happy with the attitude of our players but I am not happy with this [the defensive record],” he says.
“We have to improve more our defence. We are very good in our high press [in forward areas] but as we don’t control all the game and we let the opponent have the ball we have been in trouble defensively.
“In Brisbane, we had the energy to press in the first half. Then they only have two shots.
“It was the same against Western Sydney [last Friday’s 3-2 win at Bankwest Stadium]. We pressed well, but we conceded a goal early. It happens sometimes.
“We are very effective when we can do this and we know we have to improve.”
He is already a great admirer of Maclaren, as much for his workrate as his predatory powers in the penalty box.
“His performance is fantastic [in scoring goals]. But we have to consider his fantastic work and his high press. He does a very good job in this, it is very important in our style.”
Michael Lynch is The Age’s chief soccer reporter and also reports on motor sport and horseracing