diff --git a/README.md b/README.md
index 2774b65..22b8b9a 100644
--- a/README.md
+++ b/README.md
@@ -353,6 +353,7 @@ console.log('re2_res : ' + re2_res); // prints: re2_res : abc,a,b,c
 
 ## Release history
 
+- 1.20.3 *Fix: subsequent numbers are incorporated into group if they would form a legal group reference.*
 - 1.20.2 *Fix: added a missing C++ file, which caused a bug on Alpine Linux. Thx, [rbitanga-manticore](https://github.com/rbitanga-manticore).*
 - 1.20.1 *Fix: files included in the npm package to build the C++ code.*
 - 1.20.0 *Updated RE2. New version uses `abseil-cpp` and required the adaptation work. Thx, [Stefano Rivera](https://github.com/stefanor).*
diff --git a/lib/replace.cc b/lib/replace.cc
index 2a214e9..5eaeb8f 100644
--- a/lib/replace.cc
+++ b/lib/replace.cc
@@ -142,6 +142,12 @@ inline std::string replace(const char *data, size_t size, const std::vector<re2:
 								result += (std::string)groups[index2];
 								continue;
 							}
+							else if (index && index < groups.size())
+							{
+								result += (std::string)groups[index];
+								result += ch;
+								continue;
+							}
 							result += '$';
 							result += '0' + index;
 							result += ch;
diff --git a/tests/test_replace.js b/tests/test_replace.js
index 0fa23f6..b45872c 100644
--- a/tests/test_replace.js
+++ b/tests/test_replace.js
@@ -334,5 +334,47 @@ unit.add(module, [
     var re = new RE2(/b(?<a>1)? & (?<b>2)?y/);
     var result = re.replace('ab & yz', replacer);
     eval(t.TEST("result === 'az'"));
+  },
+  function test_replaceGroupSimple(t) {
+    'use strict';
+
+    var re = new RE2(/(2)/);
+
+    var result = re.replace('123', '$0');
+    eval(t.TEST("result === '1$03'"));
+    result = re.replace('123', '$1');
+    eval(t.TEST("result === '123'"));
+    result = re.replace('123', '$2');
+    eval(t.TEST("result === '1$23'"));
+
+    result = re.replace('123', '$00');
+    eval(t.TEST("result === '1$003'"));
+    result = re.replace('123', '$01');
+    eval(t.TEST("result === '123'"));
+    result = re.replace('123', '$02');
+    eval(t.TEST("result === '1$023'"));
+  },
+  function test_replaceGroupCases(t) {
+    'use strict';
+
+    var re = new RE2(/(test)/g);
+    var result = re.replace('123', '$1$20');
+    eval(t.TEST("result === '123'"));
+
+    re = new RE2(/(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)/g);
+    result = re.replace('abcdefghijklmnopqrstuvwxyz123', '$10$20');
+    eval(t.TEST("result === 'jb0wo0123'"));
+
+    re = new RE2(/(.)(.)(.)(.)(.)/g);
+    result = re.replace('abcdefghijklmnopqrstuvwxyz123', '$10$20');
+    eval(t.TEST("result === 'a0b0f0g0k0l0p0q0u0v0z123'"));
+
+    re = new RE2(/(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)/g);
+    result = re.replace('abcdefghijklmnopqrstuvwxyz123', '$10$20');
+    eval(t.TEST("result === 'jtvwxyz123'"));
+
+    re = new RE2(/abcd/g);
+    result = re.replace('abcd123', '$1$2');
+    eval(t.TEST("result === '$1$2123'"));
   }
 ]);