diff --git a/internal/controller/postgrescluster/controller.go b/internal/controller/postgrescluster/controller.go
index 2dac82621..6bd0b2e7b 100644
--- a/internal/controller/postgrescluster/controller.go
+++ b/internal/controller/postgrescluster/controller.go
@@ -259,6 +259,11 @@ func (r *Reconciler) Reconcile(
 	}
 
 	pgParameters := postgres.NewParameters()
+	// K8SPG-577
+	// K8SPG-884: pg_stat_statements must come before pg_stat_monitor
+	if cluster.Spec.Extensions.PGStatStatements {
+		pgstatstatements.PostgreSQLParameters(&pgParameters)
+	}
 	// K8SPG-375
 	if cluster.Spec.Extensions.PGStatMonitor {
 		pgstatmonitor.PostgreSQLParameters(&pgParameters)
@@ -266,10 +271,6 @@ func (r *Reconciler) Reconcile(
 	if cluster.Spec.Extensions.PGAudit {
 		pgaudit.PostgreSQLParameters(&pgParameters)
 	}
-	// K8SPG-577
-	if cluster.Spec.Extensions.PGStatStatements {
-		pgstatstatements.PostgreSQLParameters(&pgParameters)
-	}
 	pgbackrest.PostgreSQL(cluster, &pgParameters, backupsSpecFound)
 	pgmonitor.PostgreSQLParameters(cluster, &pgParameters)
 
diff --git a/internal/controller/postgrescluster/controller_test.go b/internal/controller/postgrescluster/controller_test.go
index e31169f4f..73723d63d 100644
--- a/internal/controller/postgrescluster/controller_test.go
+++ b/internal/controller/postgrescluster/controller_test.go
@@ -651,4 +651,119 @@ spec:
 			Expect(event).To(ContainSubstring("PG 12 will no longer receive updates. We recommend upgrading."))
 		})
 	})
+
+	Context("PG Extensions", func() {
+		var cluster *v1beta1.PostgresCluster
+
+		BeforeEach(func() {
+			cluster = create(`
+metadata:
+  name: test-cluster
+spec:
+  postgresVersion: 13
+  image: postgres
+  instances:
+  - name: instance1
+    initContainer:
+      image: pg-operator
+    dataVolumeClaimSpec:
+      accessModes:
+      - "ReadWriteMany"
+      resources:
+        requests:
+          storage: 1Gi
+  extensions:
+    pgStatMonitor: false
+    pgStatStatements: false
+    pgAudit: false
+`)
+			Expect(reconcile(cluster)).To(BeZero())
+		})
+
+		AfterEach(func() {
+			ctx := context.Background()
+
+			if cluster != nil {
+				Expect(client.IgnoreNotFound(
+					suite.Client.Delete(ctx, cluster),
+				)).To(Succeed())
+
+				// Remove finalizers, if any, so the namespace can terminate.
+				Expect(client.IgnoreNotFound(
+					suite.Client.Patch(ctx, cluster, client.RawPatch(
+						client.Merge.Type(), []byte(`{"metadata":{"finalizers":[]}}`))),
+				)).To(Succeed())
+			}
+		})
+
+		getSharedLibraries := func(cfg map[string]any) string {
+			Expect(cfg["bootstrap"]).ToNot(BeZero())
+			bootstrap, ok := cfg["bootstrap"].(map[string]any)
+			Expect(ok).To(BeTrue())
+
+			Expect(bootstrap["dcs"]).ToNot(BeZero())
+			dcs, ok := bootstrap["dcs"].(map[string]any)
+			Expect(ok).To(BeTrue())
+
+			Expect(dcs["postgresql"]).ToNot(BeZero())
+			postgresql, ok := dcs["postgresql"].(map[string]any)
+			Expect(ok).To(BeTrue())
+
+			Expect(postgresql["parameters"]).ToNot(BeZero())
+			parameters, ok := postgresql["parameters"].(map[string]any)
+			Expect(ok).To(BeTrue())
+
+			Expect(parameters["shared_preload_libraries"]).ToNot(BeZero())
+			libraries, ok := parameters["shared_preload_libraries"].(string)
+			Expect(ok).To(BeTrue())
+
+			return libraries
+		}
+
+		It("appends pg_stat_monitor after pg_stat_statements", func() {
+			ctx := context.Background()
+			orig := cluster.DeepCopy()
+
+			cluster.Spec.Extensions.PGStatMonitor = true
+			cluster.Spec.Extensions.PGAudit = true
+
+			Expect(suite.Client.Patch(ctx, cluster, client.MergeFrom(orig))).To(Succeed())
+			Expect(reconcile(cluster)).To(BeZero())
+			Expect(cluster.Status.Patroni.SystemIdentifier).To(BeZero())
+
+			ccm := &corev1.ConfigMap{}
+			Expect(suite.Client.Get(ctx, client.ObjectKey{
+				Namespace: test.Namespace.Name, Name: cluster.Name + "-config",
+			}, ccm)).To(Succeed())
+			Expect(ccm.Data["patroni.yaml"]).ToNot(BeZero())
+
+			var cfg map[string]any
+			Expect(yaml.Unmarshal([]byte(ccm.Data["patroni.yaml"]), &cfg)).To(Succeed())
+
+			libraries := getSharedLibraries(cfg)
+			Expect(libraries).To(Equal("pg_stat_monitor,pgaudit"))
+
+			orig = cluster.DeepCopy()
+
+			cluster.Spec.Extensions.PGStatStatements = true
+			cluster.Spec.Extensions.PGStatMonitor = true
+			cluster.Spec.Extensions.PGAudit = true
+
+			Expect(suite.Client.Patch(ctx, cluster, client.MergeFrom(orig))).To(Succeed())
+			Expect(reconcile(cluster)).To(BeZero())
+			Expect(cluster.Status.Patroni.SystemIdentifier).To(BeZero())
+
+			ccm = &corev1.ConfigMap{}
+			Expect(suite.Client.Get(ctx, client.ObjectKey{
+				Namespace: test.Namespace.Name, Name: cluster.Name + "-config",
+			}, ccm)).To(Succeed())
+			Expect(ccm.Data["patroni.yaml"]).ToNot(BeZero())
+
+			var cfg2 map[string]any
+			Expect(yaml.Unmarshal([]byte(ccm.Data["patroni.yaml"]), &cfg2)).To(Succeed())
+
+			libraries = getSharedLibraries(cfg2)
+			Expect(libraries).To(Equal("pg_stat_statements,pg_stat_monitor,pgaudit"))
+		})
+	})
 })
diff --git a/internal/pgstatmonitor/pgstatmonitor.go b/internal/pgstatmonitor/pgstatmonitor.go
index 5a2d67840..5ed6d2848 100644
--- a/internal/pgstatmonitor/pgstatmonitor.go
+++ b/internal/pgstatmonitor/pgstatmonitor.go
@@ -2,7 +2,6 @@ package pgstatmonitor
 
 import (
 	"context"
-	"strings"
 
 	"github.com/percona/percona-postgresql-operator/v2/internal/logging"
 	"github.com/percona/percona-postgresql-operator/v2/internal/postgres"
@@ -39,9 +38,6 @@ func DisableInPostgreSQL(ctx context.Context, exec postgres.Executor) error {
 }
 
 func PostgreSQLParameters(outParameters *postgres.Parameters) {
-
-	shared := outParameters.Mandatory.Value("shared_preload_libraries")
-	outParameters.Mandatory.Add("shared_preload_libraries",
-		strings.TrimPrefix(shared+",pg_stat_monitor", ","))
+	outParameters.Mandatory.AppendToList("shared_preload_libraries", "pg_stat_monitor")
 	outParameters.Mandatory.Add("pg_stat_monitor.pgsm_query_max_len", "2048")
 }
diff --git a/internal/pgstatstatements/pgstatstatement.go b/internal/pgstatstatements/pgstatstatement.go
index 3a2e42ec6..0f033d3d3 100644
--- a/internal/pgstatstatements/pgstatstatement.go
+++ b/internal/pgstatstatements/pgstatstatement.go
@@ -38,7 +38,6 @@ func DisableInPostgreSQL(ctx context.Context, exec postgres.Executor) error {
 }
 
 func PostgreSQLParameters(outParameters *postgres.Parameters) {
-
 	outParameters.Mandatory.AppendToList("shared_preload_libraries", "pg_stat_statements")
 	outParameters.Mandatory.Add("pg_stat_statements.track", "all")
 }