We have to beat them in points overall. There are three categories for points:
1) Event : these you can get by winning/almost winning clan events that have event points as part of the prize.
2) Battle : These you can get by doing clan wars. There is a max number of clan wars that count towards these points so you can only get so many.
3) Status : This is calculated using the clan's QI and Tc average. I personally bring the clan QI average down but more than make up for it on tc. The reason the 1st clan is there is because they're QI and tc averages are huge.