diff --git a/app/vmselect/promql/aggr.go b/app/vmselect/promql/aggr.go
index 46ebc43231..2555ad75f5 100644
--- a/app/vmselect/promql/aggr.go
+++ b/app/vmselect/promql/aggr.go
@@ -618,7 +618,9 @@ func newAggrFuncTopK(isReverse bool) aggrFunc {
 				})
 				fillNaNsAtIdx(n, ks[n], tss)
 			}
-			return removeNaNs(tss)
+			tss = removeNaNs(tss)
+			reverseSeries(tss)
+			return tss
 		}
 		return aggrFuncExt(afe, args[1], &afa.ae.Modifier, afa.ae.Limit, true)
 	}
@@ -683,7 +685,17 @@ func getRangeTopKTimeseries(tss []*timeseries, modifier *metricsql.ModifierExpr,
 	if remainingSumTS != nil {
 		tss = append(tss, remainingSumTS)
 	}
-	return removeNaNs(tss)
+	tss = removeNaNs(tss)
+	reverseSeries(tss)
+	return tss
+}
+
+func reverseSeries(tss []*timeseries) {
+	j := len(tss)
+	for i := 0; i < len(tss)/2; i++ {
+		j--
+		tss[i], tss[j] = tss[j], tss[i]
+	}
 }
 
 func getRemainingSumTimeseries(tss []*timeseries, modifier *metricsql.ModifierExpr, ks []float64, remainingSumTagName string) *timeseries {
diff --git a/app/vmselect/promql/exec.go b/app/vmselect/promql/exec.go
index ae8f3794a5..ee1bc2e5c7 100644
--- a/app/vmselect/promql/exec.go
+++ b/app/vmselect/promql/exec.go
@@ -86,21 +86,22 @@ func Exec(ec *EvalConfig, q string, isFirstPointOnly bool) ([]netstorage.Result,
 }
 
 func maySortResults(e metricsql.Expr, tss []*timeseries) bool {
-	fe, ok := e.(*metricsql.FuncExpr)
-	if !ok {
-		return true
-	}
-	switch fe.Name {
-	case "sort", "sort_desc",
-		"sort_by_label", "sort_by_label_desc",
-		"topk", "bottomk",
-		"topk_max", "topk_min", "topk_avg", "topk_median",
-		"bottomk_max", "bottomk_min", "bottomk_avg", "bottomk_median",
-		"outliersk":
-		return false
-	default:
-		return true
+	switch v := e.(type) {
+	case *metricsql.FuncExpr:
+		switch strings.ToLower(v.Name) {
+		case "sort", "sort_desc",
+			"sort_by_label", "sort_by_label_desc":
+			return false
+		}
+	case *metricsql.AggrFuncExpr:
+		switch strings.ToLower(v.Name) {
+		case "topk", "bottomk", "outliersk",
+			"topk_max", "topk_min", "topk_avg", "topk_median",
+			"bottomk_max", "bottomk_min", "bottomk_avg", "bottomk_median":
+			return false
+		}
 	}
+	return true
 }
 
 func timeseriesToResult(tss []*timeseries, maySort bool) ([]netstorage.Result, error) {