Benefiting from his better championship standing, Tomczyk had led in the closing stages but when Premat battled his way past with only five laps remaining, it looked as though Frenchman was going to be allowed to complete his first DTM win.
However, despite pulling out a significant lead immediately, Premat had a pang of conscience - no doubt massaged by calls from the pit wall - to allow Tomczyk through to claim a crucial win that moves him up to second in the standings, behind his team-mate Mattias Ekstrom who finished third, albeit not before having looked odds on for the win early on.
Only Audi's second win of the season, the A4 was clearly the car to have around the twisting Dutch circuit and although Mercedes did all they could to play themselves back into contention with a number of different strategies, fifth, seventh and eighth was the best that they could manage.
Scheider takes Zandvoort pole
From the start, pole sitter Timo Scheider got the start he needed to sneak ahead, only for Ekstrom to get the better of him through Tarzan and take the lead of the race. Just behind, Paul di Resta was turned around in the first corner melee and slipped to the back of the 18-car field, depleted by Vanina Ickx's withdrawal and a failure to start for Daniel La Rosa on the warm-up lap.
Audi dominated the leading positions by the end of the first lap, Ekstrom ahead of Scheider, Tomczyk, Premat and Mike Rockenfeller, Bruno Spengler leading the Mercedes charge in sixth place, with Christian Abt seventh and Alex Margaritis eighth, the Greek driver making a demon start from 15th on the grid.
Quickly Audi established a grip on the race, the top five all pulling away from Spengler as the first round of pit stops underway on lap six, Spengler, Abt, Margaritis, Markus Winkelhock and an already delayed Lucas Luhr taking the plunge first.
Tomczyk, Premat, Gary Paffett and Mika Hakkinen followed suit a lap later in the hope an early stop would give them the advantage over the leaders. The first signs that a stop in the early stages would prove crucial became immediately obvious when Scheider pitted a lap later than Tomczyk and Premat, yet emerged behind his team-mates having been ahead beforehand.
A likely prompt for those yet to stop to stay out as long as possible in the hope the circuit would come back to them and for those who had pitted to pit again for their second stop whilst they have the advantage, the race slipped into a battle of tactical minds.
Indeed, by lap 13 Premat, Tomczyk, Spengler and Hakkinen were all back in the pit lane for their second stop, plummeting to the back of the field but biding their time for those in front to succumb to their inevitable stops. Ekstrom duly responded on lap 14 by completing his first pit stop, emerging behind Scheider briefly before the German pitted again.
With the majority of the field having pitted at least once, Jamie Green, Mathias Lauda and Susie Stoddart, all having started from the back of the field, found themselves filling the top three but without having made one stop. Indeed, the Mercedes trio were leaving it remarkably late, the last of them waiting until lap 23 to make that stop. Stoddart had been that driver but having led briefly, she found any hopes of an advantage ruined by a very long second pit stop.
As the pit stops gradually became completed, an order began to shake out, those who had stopped latest finding themselves severely disadvantaged, meaning the likes of Ekstrom, Tom Kristensen and Rockenfeller were significantly out of position now.
Tomczyk now led having gradually risen the order over the course of the race, but he was being placed under increasing - if friendly - pressure from Premat in the year-old Phoenix A4. However, while most expected the order to remain the same to the chequered flag, Premat managed to get alongside Tomczyk heading into Scheivlak and snare the lead. Once free, the former GP2 driver simply sprinted away over the remaining five laps giving the impression that he was about to complete his first ever touring car victory.
Somewhat unsurprisingly though Premat gave in to team needs and subsequently slowed enough to allow Tomczyk to take a fortuitous, but nonetheless hard-fought, victory, the German adding to his maiden triumph in Spain last season.
A remarkably close race, not blighted by the safety car that had affected the last few races, just 14 seconds covered the top 14 positions after more than an hour of racing.
Even so, it was Audi that commanded the leading positions with Ekstrom claiming an excellent third place after a stunning drive over the final few laps. The Swede had been running an effective seventh after the pit stops, but after battling his way past Hakkinen, was allowed straight into fifth by Abt.
The championship leader duly embarked on a tussle with an ailing Spengler heading into the final lap and managed to make the move on him for fourth at the Masters corner. Just to complete his day, Scheider slowed coming onto the final straight to let him claim third and thus extend his advantage to eight points, now over Tomczyk.
Scheider finished fourth, the German arguably the quickest driver on the track but let down by a disappointing start, a less than perfect strategy and then several laps tucked up behind Spengler before eventually putting a move on the Canadian three laps from the end. Fourth equals his best result of the season.
Spengler was a rather anonymous fifth, unable to tackle the onslaught of Audis and while a good strategy always kept him in contention, the C-Class' appeared inferior in the race. Abt was an impressive sixth for his best result of the season, while Hakkinen and Margaritis rounded out the points positions in seventh and eighth.
In the standings, Ekstrom heads into the eighth of ten rounds at the Nurburgring with 38 points, eight up on Tomczyk now, who jumped from fifth to second in the standings in the process. Spengler is now third on 27 points, with Bernd Schneider down to fourth after another disappointing race to 12th.