diff --git a/src/core/net/ip6.cpp b/src/core/net/ip6.cpp
index 4f5d46fa3..23836592c 100644
--- a/src/core/net/ip6.cpp
+++ b/src/core/net/ip6.cpp
@@ -1316,7 +1316,16 @@ const NetifUnicastAddress *Ip6::SelectSourceAddress(MessageInfo &aMessageInfo)
         }
 
         candidatePrefixMatched = destination->PrefixMatch(*candidateAddr);
-        overrideScope          = (candidatePrefixMatched >= addr->mPrefixLength) ? addr->GetScope() : destinationScope;
+
+        if (candidatePrefixMatched >= addr->mPrefixLength)
+        {
+            candidatePrefixMatched = addr->mPrefixLength;
+            overrideScope          = addr->GetScope();
+        }
+        else
+        {
+            overrideScope = destinationScope;
+        }
 
         if (rvalAddr == NULL)
         {