diff --git a/py_wake/tests/test_windturbines/test_power_ct_wind_turbines.py b/py_wake/tests/test_windturbines/test_power_ct_wind_turbines.py
index ffef4fe20a9a191dd6fd07bfd5b208735190fb95..f4f282a6e76b3e09d9832d4dca3af857cda6fc8c 100644
--- a/py_wake/tests/test_windturbines/test_power_ct_wind_turbines.py
+++ b/py_wake/tests/test_windturbines/test_power_ct_wind_turbines.py
@@ -191,8 +191,8 @@ def test_PowerCtXr():
     u_p, p_c, ct_c = v80_upct.copy()
 
     ds = xr.Dataset(
-        data_vars={'power': (['ws', 'boost'], np.array([p_c, p_c * 2]).T),
-                   'ct': (['ws', 'boost'], np.array([ct_c, ct_c]).T)},
+        data_vars={'ct': (['ws', 'boost'], np.array([ct_c, ct_c]).T),
+                   'power': (['ws', 'boost'], np.array([p_c, p_c * 2]).T)},
         coords={'boost': [0, 1], 'ws': u_p, }).transpose('boost', 'ws')
     curve = PowerCtXr(ds, 'w')
     u = np.linspace(3, 25, 10)
diff --git a/py_wake/wind_turbines/power_ct_functions.py b/py_wake/wind_turbines/power_ct_functions.py
index b914b1d833f00bda2d1449a3a1272bfc7a96f3cb..dc77f7ec15832859b37ff3978cdf8a39a13c8b78 100644
--- a/py_wake/wind_turbines/power_ct_functions.py
+++ b/py_wake/wind_turbines/power_ct_functions.py
@@ -426,6 +426,7 @@ class PowerCtXr(PowerCtNDTabular):
         assert 'power' in ds
         assert 'ct' in ds
         assert 'ws' in ds.dims
+        ds = ds[['power', 'ct']]
         power_arr, ct_arr = ds.to_array()
 
         if list(power_arr.dims).index('ws') > 0: