diff --git a/singleflight/singleflight.go b/singleflight/singleflight.go
index 7c7fc50..8473fb7 100644
--- a/singleflight/singleflight.go
+++ b/singleflight/singleflight.go
@@ -144,9 +144,9 @@
 			c.err = errGoexit
 		}
 
-		c.wg.Done()
 		g.mu.Lock()
 		defer g.mu.Unlock()
+		c.wg.Done()
 		if g.m[key] == c {
 			delete(g.m, key)
 		}