Two late dismissals for Molesey allowed strikes from Josh Kelly and Roscoe Dsane to send Walton Casuals into the next round of the FA Cup.
The result saw Kelly take his tally to four goals in three games, and Dsane add his second of the season after Luke Holness’ first minute opener.
Having become the club’s youngest ever FA Cup goalscorer in last year’s Preliminary Round, he continued traditions with a well-placed effort in the first attack of the game.
The Moles came close soon after, and were halted only by the offside flag heading the ball into the net inside 10 minutes.
Ronald Sobowale’s attempt of winning a penalty midway through the first half resulted in a yellow card for simulation, but he looked to be the main threat from the visitors with a handful of close chances.
After an even first half, Molesey finally broke through on the hour mark with an unfortunate slip allowing Josh Andrew to go one-on-one and beat Denzel Gerrar with a scuffed shot.
Substitute Dsane came close to an immediate impact with a shot drilled narrowly wide, while Maidenhead United youngster Kelly forced a superb save from keeper Liam Allen.
As the two sides began to prepare for a Tuesday night replay, substitute Dre Grobler was giving his marching orders without even touching the ball. The midfielder’s first involvement in the game came through a foul on tricky midfielder Luke Holness, before stamping on the youngster in front of the referee.
And just two minutes later, the visitors were reduced to nine men for dissent after comments made to the referee saw Olu Akinsanya given his marching orders.
The Stags made full use of the additional men, and Kelly struck from 15 yards to return the lead to the hosts with their first attack following the drama.
Experienced forward Dsane soon completed the scoring just four minutes later, with a well-placed shot into the bottom corner crushing an already deflated Molesey.
Casuals defender Joe Hicks almost made it four in the closing stages, but was unable to test Allen when finding space on the edge of the box.
The Stags now go into Monday’s FA Cup First Qualifying Round draw, with £3,000 in prize money on offer in the next stage of the competition.
Walton Casuals: Denzel Gerrar, Samuel Labinjo (Jack Battie 77), Dujon Desagurante, Alex Kelly, Harry Mills, Joe Hicks, Sean McCormack (Alfie Taylor 89), Daryl Coleman, Josh Kelly, Lartey Sarpong (Roscoe Dsane 58), Luke Holness
Subs Not Used: Evander Lopes, Stuart Baldwin, Fraser Trigwell
Goals: Luke Holness (1), Josh Kelly (82), Roscoe Dsane (86)
Molesey: Liam Allen, Taylor Roles, Ato Okai, Craig Lewington, Antonio Simeone, Rhys Paul, Josh Andrew (De Grobler 78), Ross Chalke (Ashby Charles 78), Olu Akinsanya, Ronald Sobowale, Ashley Lodge.
Subs Not Used: Ryan David, James King, Darius Hervi.
Goals: Josh Andrew (62)