Who wins if two players meet victory conditions in same end phase?

By Lise2, in Chaos in the Old World

In the game we played yesterday, Nurgle(me) got to 53 VP in the same end phase as Slaanesh got his "Slaanesh wins!" dial advancement. Who won? Slaanesh's player said we both won.

Lise said:

In the game we played yesterday, Nurgle(me) got to 53 VP in the same end phase as Slaanesh got his "Slaanesh wins!" dial advancement. Who won? Slaanesh's player said we both won.

"Note that the four conditions are checked in order, and
the game ends immediately when one of them is true." (p. 22)

Order being:

#1: Threat dial (if tie, then VP)

#2: 50+ VP (if tie, highest Threat wins)

#3: 5 Regions ruined (VP, if tie, then highest Threat)

#4: OW wins