diff --git a/autoload/ingo/subst.vim b/autoload/ingo/subst.vim
index 88aac49..0c14b04 100644
--- a/autoload/ingo/subst.vim
+++ b/autoload/ingo/subst.vim
@@ -1,6 +1,8 @@
 " ingo/subst.vim: Functions for substitutions.
 "
 " DEPENDENCIES:
+"   - ingo/format.vim autoload script
+"   - ingo/subst/replacement.vim autoload script
 "
 " Copyright: (C) 2013-2018 Ingo Karkat
 "   The VIM LICENSE applies to this script; see ':help copyright'.
@@ -142,7 +144,8 @@ function! ingo#subst#Indexed( expr, pattern, replacement, indices, ... )
 "* INPUTS:
 "   a:expr  Text to be transformed.
 "   a:pattern   Regular expression.
-"   a:replacement       Replacement. |sub-replace-expression| is not supported.
+"   a:replacement       Replacement. Handles |sub-replace-expression|, & and \0,
+"                       \1 .. \9, and \r\n\t\b (but not \u, \U, etc.)
 "   a:indices   List of 0-based indices whose corresponding matches are
 "               replaced. A String value of "g" replaces globally, just like
 "               substitute(..., 'g').
@@ -167,7 +170,7 @@ endfunction
 function! s:IndexReplacer( context )
     let a:context.matchCnt += 1
     execute 'let l:isSelected = index(a:context.indices, a:context.matchCnt - 1)' (a:context.isInvert ? '==' : '!=') '-1'
-    return (l:isSelected ? a:context.replacement : submatch(0))
+    return ingo#subst#replacement#DefaultReplacementOnPredicate(l:isSelected, a:context)
 endfunction
 
 let &cpo = s:save_cpo
diff --git a/tests/subst/t1000-Indexed.vim b/tests/subst/t1000-Indexed.vim
index 4a24e7a..36b4eb3 100644
--- a/tests/subst/t1000-Indexed.vim
+++ b/tests/subst/t1000-Indexed.vim
@@ -1,7 +1,7 @@
 " Test substitution of indexed matches.
 
 call vimtest#StartTap()
-call vimtap#Plan(9)
+call vimtap#Plan(13)
 
 call vimtap#Is(ingo#subst#Indexed('foobar is loosie origon', 'o', 'X', 'g'), 'fXXbar is lXXsie XrigXn', 'global substitution')
 call vimtap#Is(ingo#subst#Indexed('foobar is loosie origon', 'o', 'X', [3]), 'foobar is loXsie origon', 'substitute single index')
@@ -14,4 +14,9 @@ call vimtap#Is(ingo#subst#Indexed('foobar is loosie origon', 'o', 'X', [-1]), 'f
 call vimtap#Is(ingo#subst#Indexed('foobar is loosie origon', 'o', 'X', [2, 3, 4], 0), 'foobar is lXXsie Xrigon', 'substitute without inversion')
 call vimtap#Is(ingo#subst#Indexed('foobar is loosie origon', 'o', 'X', [2, 3, 4], 1), 'fXXbar is loosie origXn', 'substitute with inversion')
 
+call vimtap#Is(ingo#subst#Indexed('foobar is loosie origon', 'o', '&&', [0, 1, 2, 3, 5]), 'foooobar is loooosie origoon', 'substitution with &')
+call vimtap#Is(ingo#subst#Indexed('foobar is loosie origon', 'o', '\t', [1, 3]), "fo\tbar is lo\tsie origon", 'substitution with \t')
+call vimtap#Is(ingo#subst#Indexed('foobar is loosie origon', '\(.\)\(oo\)\(.\)', '\3\2\1', [1]), 'foobar is soolie origon', 'substitution with capture groups')
+call vimtap#Is(ingo#subst#Indexed('foobar is loosie origon', 'o', '\=toupper(repeat(submatch(0), 3))', [1, 3]), 'foOOObar is loOOOsie origon', 'substitution with sub-replace-expression')
+
 call vimtest#Quit()