diff --git a/components/script/dom/textcontrol.rs b/components/script/dom/textcontrol.rs
index 0b8870b1996..2b47fcd00a4 100644
--- a/components/script/dom/textcontrol.rs
+++ b/components/script/dom/textcontrol.rs
@@ -21,7 +21,16 @@ pub trait TextControl: DerivedFrom<EventTarget> + DerivedFrom<Node> {
 
     // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectionstart
     fn set_dom_selection_start(&self, start: u32) {
-        self.set_selection_range(start, self.dom_selection_end(), self.selection_direction());
+        // Step 2
+        let mut end = self.dom_selection_end();
+
+        // Step 3
+        if end < start {
+            end = start;
+        }
+
+        // Step 4
+        self.set_selection_range(start, end, self.selection_direction());
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectionend
diff --git a/tests/wpt/metadata/html/semantics/forms/textfieldselection/selection-start-end.html.ini b/tests/wpt/metadata/html/semantics/forms/textfieldselection/selection-start-end.html.ini
deleted file mode 100644
index 1cd51a8db16..00000000000
--- a/tests/wpt/metadata/html/semantics/forms/textfieldselection/selection-start-end.html.ini
+++ /dev/null
@@ -1,5 +0,0 @@
-[selection-start-end.html]
-  type: testharness
-  [Setting selectionStart to a value larger than selectionEnd should increase selectionEnd]
-    expected: FAIL
-