It was the first podium for the team and the Spanish driver since he finished runner-up in Canada in June, and it came after a run of four events in which he didn’t better fifth place.
Alonso started the Zandvoort race in fifth but actually dropped a place at the start by pitting for intermediate tyres on the second lap rather than the opening tour.
He subsequently made good progress up to third but lost around six seconds due to a wheelgun failure when he pitted on lap 48.
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That meant he had to re-pass Carlos Sainz before setting the fastest lap as he chased down Sergio Perez. He then gained second from the Mexican during the chaotic late storm.
At the resumption after the red flag, Alonso potentially had a shot at a win, but leader Max Verstappen got the jump on him, and he finished 3.7 seconds behind the local hero.
Alonso told his team “we will win one race soon, we are getting closer” after he took the flag.
“The good thing was that he was in control all the time,” Krack told Autosport when asked about Alonso’s charging race.
“And he was always the master of the situation I would say, and this was key obviously also in such conditions to never go off.
“There were some situations where it was really about surviving which he managed, and then at the end if the opportunity would have been there [to pass Verstappen], he would have tried.
“You saw also in great style how fast he was in the first four or five races, to come back [after the stop delay] and pass the two cars, it was just incredible.
“And then the rain at the end staying out also, because the rain was so torrential we were quite sure that there would be an incident, but you hope obviously it's not you creating that incident!"
Krack acknowledged that it was good to end the drought since the last top three finish.
"After all these podiums in the first half of the season, and then more difficult races, now finally in a very difficult weekend we managed to get another podium, which is great," he added. "Great team effort from everybody, to be honest.
“All July the lights were never off in the campus. We brought new parts here, we'll bring new parts again to the next races. So we really want to try and keep fighting as much as we can in this battle, and see where we end up at the end."
Krack suggested that the major new floor package introduced at Zandvoort had paid off.
"You try to bring parts to the car, but obviously with the difficult conditions that we had here and the changing conditions the data analysis is also not an easy one,” he said.
“But everything points in the right direction. I think we made a small step in Spa, I think we made another one here, but we also need to confirm them over the next races."
Regarding prospects for the next race in Monza, he added: "We have to see. We worked quite hard now over the last weeks on our package in order to improve the straight line, to improve the DRS, so it would be a nice test to see."
