diff --git a/lib/commands/help.js b/lib/commands/help.js
index 40f5ad9b30092..c390f1a5bb2dd 100644
--- a/lib/commands/help.js
+++ b/lib/commands/help.js
@@ -61,9 +61,10 @@ class Help extends BaseCommand {
     const f = `${manroot}/${manSearch}/?(npm-)${section}.[0-9]*`
     let mans = await glob(f)
     mans = mans.sort((a, b) => {
-      // Because of the glob we know the manNumberRegex will pass
-      const aManNumber = a.match(manNumberRegex)[1]
-      const bManNumber = b.match(manNumberRegex)[1]
+      // Because the glob is (subtly) different from manNumberRegex,
+      // we can't rely on it passing.
+      const aManNumber = (a.match(manNumberRegex) || Infinity)[1]
+      const bManNumber = (b.match(manNumberRegex) || Infinity)[1]
 
       // man number sort first so that 1 aka commands are preferred
       if (aManNumber !== bManNumber) {