diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index e725285298a0..182323b1acc5 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -925,6 +925,8 @@ chk_prio_nr()
 {
 	local mp_prio_nr_tx=$1
 	local mp_prio_nr_rx=$2
+	local mpj_syn=$3
+	local mpj_syn_ack=$4
 	local count
 	local dump_stats
 
@@ -952,6 +954,30 @@ chk_prio_nr()
 		echo "[ ok ]"
 	fi
 
+	printf "%-39s %s" " " "bkp syn"
+	count=$(get_counter ${ns1} "MPTcpExtMPJoinSynBackupRx")
+	if [ -z "$count" ]; then
+		echo -n "[skip]"
+	elif [ "$count" != "$mpj_syn" ]; then
+		echo "[fail] got $count JOIN[s] syn with Backup expected $mpj_syn"
+		ret=1
+		dump_stats=1
+	else
+		echo -n "[ ok ]"
+	fi
+
+	echo -n " - synack   "
+	count=$(get_counter ${ns2} "MPTcpExtMPJoinSynAckBackupRx")
+	if [ -z "$count" ]; then
+		echo "[skip]"
+	elif [ "$count" != "$mpj_syn_ack" ]; then
+		echo "[fail] got $count JOIN[s] synack with Backup expected $mpj_syn_ack"
+		ret=1
+		dump_stats=1
+	else
+		echo "[ ok ]"
+	fi
+
 	if [ "${dump_stats}" = 1 ]; then
 		echo Server ns stats
 		ip netns exec $ns1 nstat -as | grep MPTcp
@@ -1557,7 +1583,7 @@ backup_tests()
 	ip netns exec $ns2 ./pm_nl_ctl add 10.0.3.2 flags subflow,backup
 	run_tests $ns1 $ns2 10.0.1.1 0 0 0 slow nobackup
 	chk_join_nr "single subflow, backup" 1 1 1
-	chk_prio_nr 0 1
+	chk_prio_nr 0 1 1 0
 
 	# single address, backup
 	reset
@@ -1567,7 +1593,7 @@ backup_tests()
 	run_tests $ns1 $ns2 10.0.1.1 0 0 0 slow backup
 	chk_join_nr "single address, backup" 1 1 1
 	chk_add_nr 1 1
-	chk_prio_nr 1 0
+	chk_prio_nr 1 0 0 0
 }
 
 add_addr_ports_tests()