Leading this charge up the order was race one winner Guintoli and Rea, the pair quickly dispatching of Haslam and going off in search of Smrz, who was still lapping respectably despite his waning tyres.
Nonetheless, Smrz was inevitably easy prey as Guintoli advanced with just four laps remaining, the Frenchman nosing ahead in his quest to consolidate his maiden WSBK victory earlier in the day with a surprise double.
However, Rea's decision to choose a harder compound of slick tyre was paying dividends over Guintoli, as well as Smrz, and when he pounced on the Ducati rider at the start of lap 20, Rea was unleashed into a lead he wouldn't relinquish over the remaining two revolutions.
A superb win for Rea given he will now require stitches in his injured finger, the victory continues his superb record at Assen having now won four of the last six races held around the Dutch circuit.
Despite missing out on the double, Guintoli leaves Assen with a massive haul of 45 points to catapult him up the championship order, while the podium also completes a very successful day for the burgeoning Effenbert Liberty team.
However, it could have been even better for the Czech outfit had Smrz been able to hold onto third position. Indeed, the Czech racer – who is yet to win a WSBK race – still looked fairly comfortable for third when he was baulked whilst attempting to lap Mark Aitchison, the Australian unintentionally nudging him wide at the high-speed Dulkersloot and forcing him onto the wet grass. With no grip, Smrz duly fell into retirement, a cruel return on what had been an accomplished ride.
His demise meant the battle for the final rostrum spot would come down to an entertaining, and rather boisterous, battle between Aprilia's Eugene Laverty and the factory BMWs. In the end, despite some fevered changes of position right up until the last bends, Laverty would prevail to record his first Aprilia podium, while Melandri's robust move on team-mate Haslam at the final corner would see him edge fourth by 0.002secs.
Several seconds further back, Sykes ended a fairly unsatisfying day in sixth position, the Kawasaki rider at least content in the knowledge that nearest championship rivals Max Biaggi and Checa couldn't take full advantage either.
Indeed, despite finishing a distant eighth behind Ayrton Badovini, Biaggi's fourth and eighth place finishes actually see him overtake Checa in the overall the standings, the Spaniard's failure to score placing him one point in arrears of the 2010 champion, while Sykes is still only 13 points behind himself.
Following his surprise podium finish in race one, Davide Giugliano completed a strong day in ninth position, ahead of countryman Michel Fabrizio, while John Hopkins, David Salom, Hiroshi Aoyama, Leon Camier and Leandro Mercado were the final point scorers between 11th and 15th.