diff --git a/pkg/querier/querier.go b/pkg/querier/querier.go
index 0f3821543e4..e9a80374cd7 100644
--- a/pkg/querier/querier.go
+++ b/pkg/querier/querier.go
@@ -18,18 +18,14 @@ import (
 	"github.com/prometheus/prometheus/promql"
 	"github.com/prometheus/prometheus/promql/parser"
 	"github.com/prometheus/prometheus/storage"
-	"github.com/prometheus/prometheus/tsdb/chunkenc"
 	"github.com/prometheus/prometheus/util/annotations"
 	"github.com/thanos-io/promql-engine/engine"
 	"github.com/thanos-io/promql-engine/logicalplan"
 	"github.com/thanos-io/thanos/pkg/strutil"
 	"golang.org/x/sync/errgroup"
 
-	"github.com/cortexproject/cortex/pkg/chunk"
-	"github.com/cortexproject/cortex/pkg/ingester/client"
 	"github.com/cortexproject/cortex/pkg/querier/batch"
 	"github.com/cortexproject/cortex/pkg/querier/lazyquery"
-	seriesset "github.com/cortexproject/cortex/pkg/querier/series"
 	querier_stats "github.com/cortexproject/cortex/pkg/querier/stats"
 	"github.com/cortexproject/cortex/pkg/tenant"
 	"github.com/cortexproject/cortex/pkg/util"
@@ -667,24 +663,3 @@ func validateQueryTimeRange(ctx context.Context, userID string, startMs, endMs i
 
 	return int64(startTime), int64(endTime), nil
 }
-
-// Series in the returned set are sorted alphabetically by labels.
-func partitionChunks(chunks []chunk.Chunk, mint, maxt int64, iteratorFunc chunkIteratorFunc) storage.SeriesSet {
-	chunksBySeries := map[string][]chunk.Chunk{}
-	for _, c := range chunks {
-		key := client.LabelsToKeyString(c.Metric)
-		chunksBySeries[key] = append(chunksBySeries[key], c)
-	}
-
-	series := make([]storage.Series, 0, len(chunksBySeries))
-	for i := range chunksBySeries {
-		series = append(series, &storage.SeriesEntry{
-			Lset: chunksBySeries[i][0].Metric,
-			SampleIteratorFn: func(it chunkenc.Iterator) chunkenc.Iterator {
-				return iteratorFunc(it, chunksBySeries[i], model.Time(mint), model.Time(maxt))
-			},
-		})
-	}
-
-	return seriesset.NewConcreteSeriesSet(true, series)
-}
diff --git a/pkg/querier/querier_test.go b/pkg/querier/querier_test.go
index bf35fee85c2..b6316bef8f3 100644
--- a/pkg/querier/querier_test.go
+++ b/pkg/querier/querier_test.go
@@ -3,6 +3,7 @@ package querier
 import (
 	"context"
 	"fmt"
+	"github.com/prometheus/prometheus/tsdb/chunkenc"
 	"strconv"
 	"strings"
 	"sync"
@@ -32,6 +33,7 @@ import (
 	"github.com/cortexproject/cortex/pkg/cortexpb"
 	"github.com/cortexproject/cortex/pkg/ingester/client"
 	"github.com/cortexproject/cortex/pkg/querier/batch"
+	"github.com/cortexproject/cortex/pkg/querier/series"
 	"github.com/cortexproject/cortex/pkg/util"
 	"github.com/cortexproject/cortex/pkg/util/chunkcompat"
 	"github.com/cortexproject/cortex/pkg/util/flagext"
@@ -1476,7 +1478,7 @@ type mockStoreQuerier struct {
 
 // Select implements storage.Querier interface.
 // The bool passed is ignored because the series is always sorted.
-func (q *mockStoreQuerier) Select(ctx context.Context, _ bool, sp *storage.SelectHints, matchers ...*labels.Matcher) storage.SeriesSet {
+func (q *mockStoreQuerier) Select(_ context.Context, _ bool, sp *storage.SelectHints, matchers ...*labels.Matcher) storage.SeriesSet {
 	// If we don't skip here, it'll make /series lookups extremely slow as all the chunks will be loaded.
 	// That flag is only to be set with blocks storage engine, and this is a protective measure.
 	if sp != nil && sp.Func == "series" {
@@ -1488,7 +1490,24 @@ func (q *mockStoreQuerier) Select(ctx context.Context, _ bool, sp *storage.Selec
 		return storage.ErrSeriesSet(err)
 	}
 
-	return partitionChunks(chunks, q.mint, q.maxt, q.chunkIteratorFunc)
+	cs := make([]storage.Series, 0, len(chunks))
+	chunksBySeries := map[string][]chunk.Chunk{}
+
+	for _, c := range chunks {
+		key := client.LabelsToKeyString(c.Metric)
+		chunksBySeries[key] = append(chunksBySeries[key], c)
+	}
+
+	for i, c := range chunksBySeries {
+		cs = append(cs, &storage.SeriesEntry{
+			Lset: chunksBySeries[i][0].Metric,
+			SampleIteratorFn: func(it chunkenc.Iterator) chunkenc.Iterator {
+				return q.chunkIteratorFunc(it, c, model.Time(mint), model.Time(maxt))
+			},
+		})
+	}
+
+	return series.NewConcreteSeriesSet(true, cs)
 }
 
 func (q *mockStoreQuerier) LabelValues(ctx context.Context, name string, _ *storage.LabelHints, labels ...*labels.Matcher) ([]string, annotations.Annotations, error) {