diff --git a/src/dom/dom.js b/src/dom/dom.js
index c6e5688..6ab0241 100644
--- a/src/dom/dom.js
+++ b/src/dom/dom.js
@@ -611,7 +611,7 @@ Element.Methods = {
     if (arguments.length == 1) return $(element.parentNode);
     var ancestors = Element.ancestors(element);
     return Object.isNumber(expression) ? ancestors[expression] :
-      Prototype.Selector.filter(ancestors, expression)[index || 0];
+      Prototype.Selector.find(ancestors, expression, index);
   },
 
   /**
@@ -647,7 +647,7 @@ Element.Methods = {
     if (!Object.isNumber(index)) index = 0;
     
     if (expression) {
-      return Prototype.Selector.filter(element.previousSiblings(), expression)[index];
+      return Prototype.Selector.find(element.previousSiblings(), expression, index);
     } else {
       return element.recursivelyCollect("previousSibling", index + 1)[index];
     }
@@ -669,7 +669,7 @@ Element.Methods = {
     if (!Object.isNumber(index)) index = 0;
     
     if (expression) {
-      return Prototype.Selector.filter(element.nextSiblings(), expression)[index];
+      return Prototype.Selector.find(element.nextSiblings(), expression, index);
     } else {
       var maximumLength = Object.isNumber(index) ? index + 1 : 1;
       return element.recursivelyCollect("nextSibling", index + 1)[index];
diff --git a/src/dom/event.js b/src/dom/event.js
index 0bd9fd1..84fda31 100644
--- a/src/dom/event.js
+++ b/src/dom/event.js
@@ -149,14 +149,10 @@
   function findElement(event, expression) {
     var element = Event.element(event);
     if (!expression) return element;
-    while (element) {
-      if (Prototype.Selector.match(element, expression)) {
-        return Element.extend(element);
-      }
-      element = element.parentNode
-    }
+    var elements = [element].concat(element.ancestors());
+    return Prototype.Selector.find(elements, expression, 0);
   }
-
+  
   /**
    *  Event.pointer(@event) -> Object
    *
diff --git a/src/dom/selector.js b/src/dom/selector.js
index 7e7470b..c327603 100644
--- a/src/dom/selector.js
+++ b/src/dom/selector.js
@@ -42,15 +42,25 @@ window.$$ = function() {
 // Implementation provided by selector engine.
 
 /**
- *  Prototype.Selector.filter(elements, expression) -> [Element...]
+ *  Prototype.Selector.find(elements, expression[, index]) -> Element
  *  - elements (Enumerable): a collection of DOM elements.
  *  - expression (String): A CSS selector.
+ #  - index: Numeric index of the match to return, or 0 if omitted.
  *
- *  Filters the given collection of elements with `expression` and returns an
- *  array of extended [[Element]] objects.
- *
- *  The only nodes returned will be those that match the given CSS selector.
+ *  Filters the given collection of elements with `expression` and returns the
+ *  first matching element (or the `index`th matching element if `index` is
+ *  specified).
 **/
+if (!Prototype.Selector.find) {
+  Prototype.Selector.find = function(elements, expression, index) {
+    if (Object.isUndefined(index)) index = 0;
+    var match = Prototype.Selector.match, length = elements.length, matchIndex = 0, i;
 
-// Implementation provided by selector engine.
+    for (i = 0; i < length; i++) {
+      if (match(elements[i], expression) && index == matchIndex++) {
+        return Element.extend(elements[i]);
+      }
+    }
+  }
+}
 
diff --git a/src/selector_engine.js b/src/selector_engine.js
index 9ec1266..45ba30c 100644
--- a/src/selector_engine.js
+++ b/src/selector_engine.js
@@ -16,16 +16,11 @@ Prototype.Selector = (function(engine) {
   function match(element, selector) {
     return engine.matches(selector, [element]).length == 1;
   }
-
-  function filter(elements, selector) {
-    return extend(engine.matches(selector, elements));
-  }
-  
+    
   return {
     engine:  engine,
     select:  select,
-    match:   match,
-    filter:  filter
+    match:   match
   };
 })(Sizzle);
 
diff --git a/test/unit/selector_engine_test.js b/test/unit/selector_engine_test.js
index dec966f..da428b0 100644
--- a/test/unit/selector_engine_test.js
+++ b/test/unit/selector_engine_test.js
@@ -41,13 +41,10 @@ new Test.Unit.Runner({
     this.assertEqual(false, Prototype.Selector.match(element, '.non_existent'));
   },
   
-  testFilter: function() {
+  testFind: function() {
     var elements = document.getElementsByTagName('*'),
-        filtered = Prototype.Selector.filter(elements, '.test_class');
-        
-    this.assert(Object.isArray(filtered));
-    this.assertEqual(2, filtered.length);
-    this.assertEqual('test_div_parent', filtered[0].id);
-    this.assertEqual('test_div_child', filtered[1].id);
+        expression = '.test_class';
+    this.assertEqual('test_div_parent', Prototype.Selector.find(elements, expression).id);
+    this.assertEqual('test_div_child', Prototype.Selector.find(elements, expression, 1).id);
   }
 });
\ No newline at end of file
diff --git a/vendor/nwmatcher/selector_engine.js b/vendor/nwmatcher/selector_engine.js
index 5bc8ac4..2d55a14 100644
--- a/vendor/nwmatcher/selector_engine.js
+++ b/vendor/nwmatcher/selector_engine.js
@@ -6,22 +6,10 @@ Prototype.Selector = (function(engine) {
     return engine.select(selector, scope || document, null, Element.extend);
   }
 
-  function filter(elements, selector) {
-    var results = [], element, i = 0;
-    while (element = elements[i++]) {
-      if (engine.match(element, selector)) {
-        Element.extend(element);
-        results.push(element);
-      }
-    }
-    return results;
-  }
-  
   return {
     engine:  engine,
     select:  select,
-    match:   engine.match,
-    filter:  filter
+    match:   engine.match
   };
 })(NW.Dom);