diff --git a/crates/typst-library/src/math/spacing.rs b/crates/typst-library/src/math/spacing.rs
index 848aca789..80bb30a02 100644
--- a/crates/typst-library/src/math/spacing.rs
+++ b/crates/typst-library/src/math/spacing.rs
@@ -47,8 +47,9 @@ pub(super) fn spacing(
         (Binary, _) if !script(l) => resolve(MEDIUM, l),
         (_, Binary) if !script(r) => resolve(MEDIUM, r),
 
-        // Thin spacing around large operators, unless next to a delimiter.
-        (Large, Opening | Fence) | (Closing | Fence, Large) => None,
+        // Thin spacing around large operators, unless to the left of
+        // an opening delimiter. TeXBook, p170
+        (Large, Opening | Fence) => None,
         (Large, _) => resolve(THIN, l),
         (_, Large) => resolve(THIN, r),
 
diff --git a/tests/ref/math/spacing.png b/tests/ref/math/spacing.png
index 317682392..0430060bb 100644
Binary files a/tests/ref/math/spacing.png and b/tests/ref/math/spacing.png differ
diff --git a/tests/typ/math/spacing.typ b/tests/typ/math/spacing.typ
index 132477f7f..87bfb0028 100644
--- a/tests/typ/math/spacing.typ
+++ b/tests/typ/math/spacing.typ
@@ -13,7 +13,7 @@ $sum x, sum(x)$ \
 $sum product x$ \
 $f(x), zeta(x), "frac"(x)$ \
 $a+dots.c+b$
-
+$f(x) sin(y)$
 ---
 // Test ignored vs non-ignored spaces.
 $f (x), f(x)$ \