diff --git a/share/completions/pip2.fish b/share/completions/pip2.fish
index 8cc6457eb..af3ef5630 100644
--- a/share/completions/pip2.fish
+++ b/share/completions/pip2.fish
@@ -3,5 +3,5 @@ if command -sq pip2
     # See discussion at https://github.com/fish-shell/fish-shell/pull/4448
     # and pip bug at https://github.com/pypa/pip/pull/4755
     # Keep this even after pip fix is upstreamed for users not on the latest pip
-    pip2 completion --fish | string replace -r "\b-c\s+pip\b" -- "-c pip2" | source
+    pip2 completion --fish | string replace -r -- " -c\s+pip\b" " -c pip2" | source
 end
diff --git a/share/completions/pip3.fish b/share/completions/pip3.fish
index 1d1da95e8..1542a5528 100644
--- a/share/completions/pip3.fish
+++ b/share/completions/pip3.fish
@@ -3,5 +3,5 @@ if command -sq pip3
     # See discussion at https://github.com/fish-shell/fish-shell/pull/4448
     # and pip bug at https://github.com/pypa/pip/pull/4755
     # Keep this even after pip fix is upstreamed for users not on the latest pip
-    pip3 completion --fish | string replace -r "\b-c\s+pip\b" -- "-c pip3" | source
+    pip3 completion --fish | string replace -r -- " -c\s+pip\b" " -c pip3" | source
 end