diff --git a/src/sort/sort.rs b/src/sort/sort.rs
index 4f3013f7b..c21802d49 100644
--- a/src/sort/sort.rs
+++ b/src/sort/sort.rs
@@ -383,11 +383,15 @@ fn permissive_f64_parse(a: &str) -> f64 {
     // because there's no way to handle both CSV and thousands separators without a new flag.
     // GNU sort treats "1,234" as "1" in numeric, so maybe it's fine.
     // GNU sort treats "NaN" as non-number in numeric, so it needs special care.
-    let sa: &str = a.split_whitespace().next().unwrap();
-    match sa.parse::<f64>() {
-        Ok(a) if a.is_nan() => std::f64::NEG_INFINITY,
-        Ok(a) => a,
-        Err(_) => std::f64::NEG_INFINITY,
+    match a.split_whitespace().next() {
+        None => std::f64::NEG_INFINITY,
+        Some(sa) => {
+            match sa.parse::<f64>() {
+                Ok(a) if a.is_nan() => std::f64::NEG_INFINITY,
+                Ok(a) => a,
+                Err(_) => std::f64::NEG_INFINITY,
+            }
+        }
     }
 }