The team served notice of their return to form this year as Daniil Kvyat claimed a podium and Daniel Ricciardo finished on his tail in fourth in China. And while Russia might not have gone to script, Marko feels the team are about to make a 'big step' with their engine, which would launch them right onto the tails of Ferrari and Mercedes.
"What we are really looking forward is the next [power unit] upgrade - how powerful it will be," Marko told Formula1.com.
"We are pretty optimistic. If the figures are right it should put us back in a situation where we can win races again on circuits like Budapest and Singapore - tracks that don’t have long straights.
[Already Red Bull have made] a big step. In fact, we hope to be a threat to Ferrari the rest of the season..."
Despite his optimism, Marko warned that the team's fluctuating form between China and Russia proved just how hard it will be to challenge the likes of Williams and Ferrari.
"China was very special - a bit out of the norm," he said.
"Daniel [Ricciardo] had the speed, yes, and in the end we were unlucky because without his puncture he could have finished second. But don’t forget Hamilton had his issues and the two Ferraris collided at the start. That will not happen at every race unfortunately.
"Looking at the Russian weekend: the engine power is super important there - we saw in qualifying that we had dropped back a bit again. We were again in the region of the Williams..."
Despite neither Kvyat nor Ricciardo scoring in Sochi, Red Bull are enjoying their best start to a campaign for two seasons. They currently sit third in the constructors' standings on 57 points - six ahead of Williams, who edged them for third in the 2015 standings.
Look out for the full - and frank - interview with Helmut Marko on Friday, exclusively on Formula1.com.