Mumbai totally dominated the match with their attacking style of play with excellent wing to wing passing to notch up their first victory in the tournament, and the biggest yet by margin, after losing their opening game, which kick-started the league, 0-3 in Kolkata.
Mumbai were keen to secure three points which they did with aplomb with a storming first half display that ripped open the Pune defence at the D Y Patil Stadium.
The visitors remained on one point after a goalless draw against Delhi Dynamos on October 14.
The goals were notched up by Moritz in the 12th, 27th and 71st minutes while Subhash Singh fired home in between in the 36th minute of a totally one-sided encounter.
Defender Johan Letzelter completed Pune's humiliation by firing in the fifth and last goal in the 85th minute.
Mumbai rode roughshod over their state rivals from across the Sahyadri range and could have been up by half a dozen goals by half time but for some alert goalkeeping by Emanuele Belardi who had to contend with a jittery defensive four in front.
Brazilian Moritz, who came on as substitute in their lost lung opener against Atletico de Kolkata on October 12, fired in the first two goals thanks in good measure to some poor defensive work from Colombian Andres Ramirez, Italian Bruno Cirilo, Dharmaraj Ravanan and Pritam Kotal and then added one more after the breather.
The first one, in the 12th minute, was a real beauty as the Brazilian uncorked a powerful left footed shot from just outside the right corner of the box to the far corner of the net with Belardi diving fruitlessly to stop the shot.
The move was initiated by a superb diagonal pass from the left wing from Lalrindika Ralte who had an outstanding game. All that Brazilian Moritz, who was unmarked, had to do was to move up a few paces and take the shot which he did with inch-perfect accuracy.

Fifteen minutes later Moritz gently tapped in a corner kick from Ralte to give Mumbai a handy 2-0 lead, a few minutes after Pune's marquee player and French World Cup winner David Trezeguet came up with a stunning reverse scissor-kick from inside the box only to see the ball hit the crossbar.
The corner was awarded when Belardi punched out a diving, angular header by Nadong Bhutia and the Pune custodian again came to his side's rescue to foil another left footed try by Ralte.
Moritz was to take advantage again of some shoddy defending, after Ramirez had been substituted by Israil Gurung, in the second half to squeeze in a shot just to the right of Belardi before defender Johan Letzelter completed Pune's misery by scoring from close range off a centre in the 85th minute.
Subhash Singh, who had also been used as a substitute by Mumbai coach Peter Reid in the first game, earlier went into the scorers' book in the 36th minute when he ran forward, after being fed superbly by teammate Jan Stohanzl from Czech Republic, and beat Belardi to the goalkeeper's left with a fine shot.
But, Subhash was guilty of squandering a 'sitter' four minutes later when he was unmarked and had only Italian Belardi to beat without being challenged and struck wide of the right post.
In total contrast was Pune who made very few attacking moves in the opening half.
Trezeguet, barring the stunning reverse bicycle kick, was largely unrecognizable and so too was Nigerian Dudu Omagbemi who has a lot of I-League experience behind him.
The game had started on a slightly rough note with two yellow cards being dished out by referee Christopher Penso within the first five minutes, Peter Costa of Mumbai and Pune's Lenny Rodrigues being the culprits of tripping rival players.
Mumbai made a few changes to their starting eleven, by bringing in Moritz, Subhash Singh and Costa.
Mumbai coach Peter Reid praised his two goal-scoring forwards Moritz and Subhash as "brilliant".
"The quality of the goals was fantastic, the hat-trick was fantastic," he said.
"We had pace down the sides (wings) and control down the middle. In attack we always looked dangerous. All of them played well," said the Englishman.
"After we scored our second goal we started controlling the game. We were disappointing against Kolkata. Today it was a really good team work. We also passed the ball well and used the width of the field," said Reid.
He also pointed out that his defence held out in the match.
"We had a clean sheet, no goals against us. I am absolutely delighted by the performance."
Moritz said that in the first game he had just landed and was jet-lagged but on Saturday he could play for 75-80 minutes "without much trouble".
"It's not easy to come back after losing 0-3. We are like a family, the boys have been amazing. We train in the hotel. Everybody stepped in. I am glad to be part of this team," he added.
Losing team coach Franco Colomba described the humiliating loss as a failure of the team as a whole and did not want to single out any one to lay the blame.
"It was a collective failure and not only of defense, midfield or frontline. We made a lot of mistakes and this is a lesson for us," he said.
"We were in the game for the first 20 minutes, had a few chances to score too but then we conceded the second goal and from that time on it was difficult for us to bounce back," said the Italian.
He, however, did not see the loss as the end of the road for his team.
"The championship is still on. Mumbai had lost 0-3 in their first game and today they won 5-0. This is football," he said.
"We will go back to Pune to work on improving our performance. We need to score points," he added.

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