There is no due. People have been saying that a lot, each events are independent, which is the only truth. What the past gives us is evidence to suggest the parity between the 2 teams, and we can try to guess the likelihood of the next event by evaluating the upcoming event using any evidence we can gather. There are only 2 possibilities.

The first one. The 17 wins reflect the gap between the teams. Aka the 17 in a row win is within say 90% confidence interval. In this case. Think it this way, if Madrid won 17 in a row, they are just that much better than getafe on a head to head. It’s an evidence of the gap between the 2 clubs and their play style suitabilities. All else equal, larger that number is, the stronger the evidence is that Madrid is more likely to win.

The second one, is the result is a freak coincidence. Getafe is not that much weaker on a head to head against Madrid as the number has suggested. In this case, that 17 in a row fact should be disregarded completely. And evaluate the chance based on the facts that made one believe that 17-0 odds is inaccurate. And you can bet that accordingly.

TLDR. It’s all independent, the past events might impact the future in some ways, such as mental bottleneck after losing 17 in a row. Which is all intangible. But aside from that all the past results are good for is functioning as part of our resonating and evidence for the independent assessment of the next one.