Doubt about index correlation

Let's say I have stock that is highly correlated to the market index, for whatever reason.

The stock is in a uptrend and is forming a continuation pattern, a flag, for example.

The index, on the other hand, is at a strong resistance level and is not showing strength.

How do you approach this situation?

 

Pairs trade. But you would be betting that they will not be correlated for a time period.