The result meant that Rec, who were second in the table on Friday afternoon, dropped to fourth.
But from kick-off it was Rec who looked the stronger side and the hosts dominated possession.
Quick one-twos and an aggressive approach kept most of play in the Sylvans half and the reds were limited to counter-attacks.
However, it was from one of these that opener came when Kyle Smith chased down a long ball to and fed Harry Hutchison to lob over Christian Povall in goal.
The goal reinvigorated the westerners and led them to dig in to chase a second.
After Rec captain Glenn Le Tissier was sin-binned, the momentum change was clear and Sylvans started to create more chances.
However, they were not able to capitalise on any of these and as Le Tissier made his way back onto the pitch, Vale Rec regained their solid structure.
Three powerful attempts were fizzed at Sylvans goalkeeper Nick Batiste, who made and continued to make brilliant saves all game and managed to keep the score at 0-1.
Approaching half-time, in a similar fashion to the first goal Smith chased down a long ball on the counter.
This time he decided to go alone and beat his man to slot the ball past Povall.
Trailing by two goals to the team seven points behind them, Rec ramped up the pressure in the second half and halved the deficit when Marlon Jardim finished a cross from Jacob Masterton-Pipet, who had been causing Sylvans issues.
Now only trailing by one, Rec kept increasing the pressure and Masteron-Pipet started hitting his stride.
With intensity rising, Batiste was one of the busiest players and out of all his saves, his best came in the 85th minute when he made an incredible reflex stop to keep his team in the lead.
Going into the dying minutes of the game, Rec went all out by repeatedly launching the ball into the Sylvans box and Jardim nearly got his brace but looked on in agony as his attempt hit the bar.
Sylvans held out until the end, taking the ball into the corner to wind the clock down to secure the three points, 2-1.
Elsewhere in the FNB Priaulx League, Belgrave Wanderers came from behind to end Rovers' unbeaten record with a 2-1 win at Port Soif and St Martin's won 1-0 in Alderney.
On Friday night, Northerners had jumped to second place with a 2-0 win over Rangers.