diff --git a/docs/changelog/139240.yaml b/docs/changelog/139240.yaml
new file mode 100644
index 0000000000000..ef5e7326452cc
--- /dev/null
+++ b/docs/changelog/139240.yaml
@@ -0,0 +1,5 @@
+pr: 139240
+summary: Don't use index() to populate rerank score array
+area: Relevance
+type: bug
+issues: []
diff --git a/x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/rank/textsimilarity/TextSimilarityRankFeaturePhaseRankCoordinatorContext.java b/x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/rank/textsimilarity/TextSimilarityRankFeaturePhaseRankCoordinatorContext.java
index 725443bc01e0d..ba095965c6f26 100644
--- a/x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/rank/textsimilarity/TextSimilarityRankFeaturePhaseRankCoordinatorContext.java
+++ b/x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/rank/textsimilarity/TextSimilarityRankFeaturePhaseRankCoordinatorContext.java
@@ -24,6 +24,7 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
 
@@ -193,9 +194,13 @@ protected InferenceAction.Request generateRequest(List<String> docFeatures) {
     }
 
     float[] extractScoresFromRankedDocs(List<RankedDocsResults.RankedDoc> rankedDocs) {
-        float[] scores = new float[rankedDocs.size()];
-        for (RankedDocsResults.RankedDoc rankedDoc : rankedDocs) {
-            scores[rankedDoc.index()] = rankedDoc.relevanceScore();
+        List<RankedDocsResults.RankedDoc> sortedRankedDocs = rankedDocs.stream()
+            .sorted(Comparator.comparingInt(RankedDocsResults.RankedDoc::index))
+            .toList();
+
+        float[] scores = new float[sortedRankedDocs.size()];
+        for (int i = 0; i < sortedRankedDocs.size(); i++) {
+            scores[i] = sortedRankedDocs.get(i).relevanceScore();
         }
         return scores;
     }