diff --git a/src/sage/libs/giac/giac.pyx b/src/sage/libs/giac/giac.pyx
index eb6fed7697e..8b81a39c700 100644
--- a/src/sage/libs/giac/giac.pyx
+++ b/src/sage/libs/giac/giac.pyx
@@ -2021,7 +2021,7 @@ class GiacFunction(Pygen):
             # FIXME? improve with a vector, or improve Pygen(list)
             right = Pygen(args).eval()
         elif n == 1:
-            right = Pygen(args[0])
+            right = Pygen(args[0]).eval()
         else:
             right = GIACNULL
         if isinstance(self, Pygen) == False: