diff --git a/quic/core/crypto/crypto_protocol.h b/quic/core/crypto/crypto_protocol.h
index f0a20cc..b2776be 100644
--- a/quic/core/crypto/crypto_protocol.h
+++ b/quic/core/crypto/crypto_protocol.h
@@ -401,6 +401,9 @@
 const QuicTag kQLVE = TAG('Q', 'L', 'V', 'E');   // Legacy Version
                                                  // Encapsulation.
 
+const QuicTag kPDP1 = TAG('P', 'D', 'P', '1');   // Path degrading triggered
+                                                 // at 1PTO.
+
 const QuicTag kPDP2 = TAG('P', 'D', 'P', '2');   // Path degrading triggered
                                                  // at 2PTO.
 
diff --git a/quic/core/quic_sent_packet_manager.cc b/quic/core/quic_sent_packet_manager.cc
index b7c3a5b..4c5026c 100644
--- a/quic/core/quic_sent_packet_manager.cc
+++ b/quic/core/quic_sent_packet_manager.cc
@@ -226,6 +226,9 @@
       use_standard_deviation_for_pto_ = true;
       rtt_stats_.EnableStandardDeviationCalculation();
     }
+    if (config.HasClientRequestedIndependentOption(kPDP1, perspective)) {
+      num_ptos_for_path_degrading_ = 1;
+    }
     if (config.HasClientRequestedIndependentOption(kPDP2, perspective)) {
       num_ptos_for_path_degrading_ = 2;
     }
diff --git a/quic/core/quic_sent_packet_manager_test.cc b/quic/core/quic_sent_packet_manager_test.cc
index 99865a0..a09afc6 100644
--- a/quic/core/quic_sent_packet_manager_test.cc
+++ b/quic/core/quic_sent_packet_manager_test.cc
@@ -4041,7 +4041,7 @@
   EXPECT_EQ(expected_delay, manager_.GetPathDegradingDelay());
 }
 
-TEST_F(QuicSentPacketManagerTest, GetPathDegradingDelayUsingPTO) {
+TEST_F(QuicSentPacketManagerTest, GetPathDegradingDelayUsing2PTO) {
   QuicConfig client_config;
   QuicTagVector options;
   options.push_back(k1PTO);
@@ -4058,6 +4058,23 @@
   EXPECT_EQ(expected_delay, manager_.GetPathDegradingDelay());
 }
 
+TEST_F(QuicSentPacketManagerTest, GetPathDegradingDelayUsing1PTO) {
+  QuicConfig client_config;
+  QuicTagVector options;
+  options.push_back(k1PTO);
+  QuicTagVector client_options;
+  client_options.push_back(kPDP1);
+  QuicSentPacketManagerPeer::SetPerspective(&manager_, Perspective::IS_CLIENT);
+  client_config.SetConnectionOptionsToSend(options);
+  client_config.SetClientConnectionOptions(client_options);
+  EXPECT_CALL(*send_algorithm_, SetFromConfig(_, _));
+  EXPECT_CALL(*network_change_visitor_, OnCongestionChange());
+  manager_.SetFromConfig(client_config);
+  EXPECT_TRUE(manager_.pto_enabled());
+  QuicTime::Delta expected_delay = 1 * manager_.GetPtoDelay();
+  EXPECT_EQ(expected_delay, manager_.GetPathDegradingDelay());
+}
+
 TEST_F(QuicSentPacketManagerTest, ClientsIgnorePings) {
   QuicSentPacketManagerPeer::SetPerspective(&manager_, Perspective::IS_CLIENT);
   QuicConfig client_config;