diff --git a/src/Microsoft.AspNetCore.Http.Abstractions/Internal/PathStringHelper.cs b/src/Microsoft.AspNetCore.Http.Abstractions/Internal/PathStringHelper.cs
new file mode 100644
index 0000000000..45b44ab1bb
--- /dev/null
+++ b/src/Microsoft.AspNetCore.Http.Abstractions/Internal/PathStringHelper.cs
@@ -0,0 +1,32 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace Microsoft.AspNetCore.Http.Internal
+{
+    internal class PathStringHelper
+    {
+        private static bool[] ValidPathChars = {
+            false, false, false, false, false, false, false, false,     // 0x00 - 0x07
+            false, false, false, false, false, false, false, false,     // 0x08 - 0x0F
+            false, false, false, false, false, false, false, false,     // 0x10 - 0x17
+            false, false, false, false, false, false, false, false,     // 0x18 - 0x1F
+            false, true,  false, false, true,  false, true,  true,      // 0x20 - 0x27
+            true,  true,  true,  true,  true,  true,  true,  true,      // 0x28 - 0x2F
+            true,  true,  true,  true,  true,  true,  true,  true,      // 0x30 - 0x37
+            true,  true,  true,  true,  false, true,  false, false,     // 0x38 - 0x3F
+            true,  true,  true,  true,  true,  true,  true,  true,      // 0x40 - 0x47
+            true,  true,  true,  true,  true,  true,  true,  true,      // 0x48 - 0x4F
+            true,  true,  true,  true,  true,  true,  true,  true,      // 0x50 - 0x57
+            true,  true,  true,  false, false, false, false, true,      // 0x58 - 0x5F
+            false, true,  true,  true,  true,  true,  true,  true,      // 0x60 - 0x67
+            true,  true,  true,  true,  true,  true,  true,  true,      // 0x68 - 0x6F
+            true,  true,  true,  true,  true,  true,  true,  true,      // 0x70 - 0x77
+            true,  true,  true,  false, false, false, true,  false,     // 0x78 - 0x7F
+        };
+
+        public static bool IsValidPathChar(char c)
+        {
+            return c < ValidPathChars.Length && ValidPathChars[c];
+        }
+    }
+}
diff --git a/src/Microsoft.AspNetCore.Http.Abstractions/PathString.cs b/src/Microsoft.AspNetCore.Http.Abstractions/PathString.cs
index 72e8d9590c..0b56e46292 100644
--- a/src/Microsoft.AspNetCore.Http.Abstractions/PathString.cs
+++ b/src/Microsoft.AspNetCore.Http.Abstractions/PathString.cs
@@ -2,8 +2,9 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Text.Encodings.Web;
+using System.Text;
 using Microsoft.AspNetCore.Http.Abstractions;
+using Microsoft.AspNetCore.Http.Internal;
 
 namespace Microsoft.AspNetCore.Http
 {
@@ -66,25 +67,83 @@ namespace Microsoft.AspNetCore.Http
         /// <returns>The escaped path value</returns>
         public string ToUriComponent()
         {
-            // TODO: Measure the cost of this escaping and consider optimizing.
             if (!HasValue)
             {
                 return string.Empty;
             }
-            var values = _value.Split(splitChar);
-            var changed = false;
-            for (var i = 0; i < values.Length; i++)
-            {
-                var value = values[i];
-                values[i] = UrlEncoder.Default.Encode(value);
 
-                if (!changed && value != values[i])
+            StringBuilder buffer = null;
+
+            var start = 0;
+            var count = 0;
+            var requiresEscaping = false;
+            for (int i = 0; i < _value.Length; ++i)
+            {
+                if (PathStringHelper.IsValidPathChar(_value[i]))
                 {
-                    changed = true;
+                    if (requiresEscaping)
+                    {
+                        // the current segment requires escape
+                        if (buffer == null)
+                        {
+                            buffer = new StringBuilder(_value.Length * 3);
+                        }
+
+                        buffer.Append(Uri.EscapeDataString(_value.Substring(start, count)));
+
+                        requiresEscaping = false;
+                        start = i;
+                        count = 0;
+                    }
+
+                    count++;
+                }
+                else
+                {
+                    if (!requiresEscaping)
+                    {
+                        // the current segument doesn't require escape
+                        if (buffer == null)
+                        {
+                            buffer = new StringBuilder(_value.Length * 3);
+                        }
+
+                        buffer.Append(_value, start, count);
+
+                        requiresEscaping = true;
+                        start = i;
+                        count = 0;
+                    }
+
+                    count++;
                 }
             }
 
-            return changed ? string.Join("/", values) : _value;
+            if (count == _value.Length && !requiresEscaping)
+            {
+                return _value;
+            }
+            else
+            {
+                if (count > 0)
+                {
+                    if (buffer == null)
+                    {
+                        buffer = new StringBuilder(_value.Length * 3);
+                    }
+
+                    if (requiresEscaping)
+                    {
+                        buffer.Append(Uri.EscapeDataString(_value.Substring(start, count)));
+                    }
+                    else
+                    {
+                        buffer.Append(_value, start, count);
+                    }
+                }
+
+                return buffer.ToString();
+            }
         }
 
         /// <summary>
@@ -335,7 +394,7 @@ namespace Microsoft.AspNetCore.Http
         /// Implicitly calls ToString().
         /// </summary>
         /// <param name="path"></param>
-        public static implicit operator string (PathString path)
+        public static implicit operator string(PathString path)
         {
             return path.ToString();
         }
diff --git a/test/Microsoft.AspNetCore.Http.Abstractions.Tests/PathStringTests.cs b/test/Microsoft.AspNetCore.Http.Abstractions.Tests/PathStringTests.cs
index 6aa15216af..b901944524 100644
--- a/test/Microsoft.AspNetCore.Http.Abstractions.Tests/PathStringTests.cs
+++ b/test/Microsoft.AspNetCore.Http.Abstractions.Tests/PathStringTests.cs
@@ -185,5 +185,21 @@ namespace Microsoft.AspNetCore.Http
 
             Assert.Equal(expectedResult, result);
         }
+
+        [Theory]
+        [InlineData("unreserved", "/abc123.-_~", "/abc123.-_~")]
+        [InlineData("colon", "/:", "/:")]
+        [InlineData("at", "/@", "/@")]
+        [InlineData("sub-delims", "/!$&'()*+,;=", "/!$&'()*+,;=")]
+        [InlineData("reserved", "/?#[]", "/%3F%23%5B%5D")]
+        [InlineData("pct-encoding", "/单行道", "/%E5%8D%95%E8%A1%8C%E9%81%93")]
+        [InlineData("mixed1", "/index/单行道=(x*y)[abc]", "/index/%E5%8D%95%E8%A1%8C%E9%81%93=(x*y)%5Babc%5D")]
+        [InlineData("mixed2", "/index/单行道=(x*y)[abc]_", "/index/%E5%8D%95%E8%A1%8C%E9%81%93=(x*y)%5Babc%5D_")]
+        public void ToUriComponentEscapeCorrectly(string category, string input, string expected)
+        {
+            var path = new PathString(input);
+
+            Assert.Equal(expected, path.ToUriComponent());
+        }
     }
 }