diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,8 @@
 # Changelog for the [`ghc-typelits-extra`](http://hackage.haskell.org/package/ghc-typelits-extra) package
 
+# 0.5.1 *October 21st 2025*
+* Compatibility with `ghc-typelits-natnormalise` 0.9.1 release
+
 # 0.5.0 *October 17th 2025*
 * Add support for GHC 9.14
 * Uses https://hackage.haskell.org/package/ghc-tcplugin-api to make supporting new GHC versions easier
diff --git a/ghc-typelits-extra.cabal b/ghc-typelits-extra.cabal
--- a/ghc-typelits-extra.cabal
+++ b/ghc-typelits-extra.cabal
@@ -1,6 +1,6 @@
 cabal-version:       3.0
 name:                ghc-typelits-extra
-version:             0.5.0
+version:             0.5.1
 synopsis:            Additional type-level operations on GHC.TypeLits.Nat
 description:
   Additional type-level operations on @GHC.TypeLits.Nat@:
diff --git a/src/GHC/TypeLits/Extra/Solver/Operations.hs b/src/GHC/TypeLits/Extra/Solver/Operations.hs
--- a/src/GHC/TypeLits/Extra/Solver/Operations.hs
+++ b/src/GHC/TypeLits/Extra/Solver/Operations.hs
@@ -133,9 +133,14 @@
   let x' = reifyEOP defs x
       y' = reifyEOP defs y
       (z,deps) = fst (runWriter (normaliseNat (mkTyConApp typeNatSubTyCon [y',x'])))
+      (z',deps') = fst (runWriter (normaliseNat (mkTyConApp typeNatSubTyCon [x',y'])))
   in  case runWriterT (isNatural z) of
-        Just (True , cs) | Set.null cs -> (y, Normalised deps)
-        Just (False, cs) | Set.null cs -> (x, Normalised deps)
+        Nothing -> case runWriterT (isNatural z') of
+          Just (True ,cs) | Set.null cs -> (x, Normalised deps') -- x >= y
+          Just (False,cs) | Set.null cs -> (y, Normalised deps') -- x < y
+          _ -> (Max x y, Untouched)
+        Just (True , cs) | Set.null cs -> (y, Normalised deps) -- y >= x
+        Just (False, cs) | Set.null cs -> (x, Normalised deps) -- y < x
         _ -> (Max x y, Untouched)
 
 mergeMin :: ExtraDefs -> ExtraOp -> ExtraOp -> NormaliseResult
@@ -143,9 +148,14 @@
   let x' = reifyEOP defs x
       y' = reifyEOP defs y
       (z,deps) = fst (runWriter (normaliseNat (mkTyConApp typeNatSubTyCon [y',x'])))
+      (z',deps') = fst (runWriter (normaliseNat (mkTyConApp typeNatSubTyCon [x',y'])))
   in  case runWriterT (isNatural z) of
-        Just (True, cs) | Set.null cs -> (x, Normalised deps)
-        Just (False,cs) | Set.null cs -> (y, Normalised deps)
+        Nothing -> case runWriterT (isNatural z') of
+          Just (True ,cs) | Set.null cs -> (y, Normalised deps') -- x >= y
+          Just (False,cs) | Set.null cs -> (x, Normalised deps') -- x < y
+          _ -> (Min x y, Untouched)
+        Just (True, cs) | Set.null cs -> (x, Normalised deps) -- y >= x
+        Just (False,cs) | Set.null cs -> (y, Normalised deps) -- y < x
         _ -> (Min x y, Untouched)
 
 mergeDiv :: ExtraOp -> ExtraOp -> Maybe NormaliseResult