diff --git a/dvaas/packet_injection.cc b/dvaas/packet_injection.cc
index d108caac..57a78bc2 100644
--- a/dvaas/packet_injection.cc
+++ b/dvaas/packet_injection.cc
@@ -153,10 +153,19 @@ absl::StatusOr<PacketTestRuns> SendTestPacketsAndCollectOutputs(
     if (packet_test_vector.input().type() == SwitchInput::DATAPLANE) {
       const Packet& packet = packet_test_vector.input().packet();
 
+      // Get corresponding control switch port for the packet's ingress port.
+      ASSIGN_OR_RETURN(const P4rtPortId sut_ingress_port,
+                       P4rtPortId::MakeFromP4rtEncoding(packet.port()));
+      ASSIGN_OR_RETURN(
+          const P4rtPortId control_switch_port,
+          parameters.mirror_testbed_port_map
+              .GetControlSwitchPortConnectedToSutPort(sut_ingress_port));
+
       // Inject to egress of control switch.
       RETURN_IF_ERROR(pins::InjectEgressPacket(
-          packet.port(), absl::HexStringToBytes(packet.hex()),
-          control_ir_p4info, &control_switch, injection_delay));
+          control_switch_port.GetP4rtEncoding(),
+          absl::HexStringToBytes(packet.hex()), control_ir_p4info,
+          &control_switch, injection_delay));
     } else {
       return absl::UnimplementedError(
           absl::StrCat("Test vector input type not supported\n",
diff --git a/dvaas/port_id_map.cc b/dvaas/port_id_map.cc
index 0ca38f43..ac393fb3 100644
--- a/dvaas/port_id_map.cc
+++ b/dvaas/port_id_map.cc
@@ -88,9 +88,28 @@ MirrorTestbedP4rtPortIdMap::GetSutPortConnectedToControlSwitchPort(
         absl::Substitute("Control port '$0' was not found in control switch "
                          "to SUT P4RT port ID map.",
                          control_port));
-  } else {
-    return it->second;
   }
+  return it->second;
+}
+
+absl::StatusOr<pins_test::P4rtPortId>
+MirrorTestbedP4rtPortIdMap::GetControlSwitchPortConnectedToSutPort(
+    const pins_test::P4rtPortId& sut_port) const {
+  // Handle implicit identity map.
+  if (!control_to_sut_port_map_.has_value()) return sut_port;
+
+  // Handle explicit map.
+  const auto it = absl::c_find_if(*control_to_sut_port_map_,
+                                  [&](const auto& control_sut_port) {
+                                    return control_sut_port.second == sut_port;
+                                  });
+  if (it == control_to_sut_port_map_->end()) {
+    return absl::NotFoundError(
+        absl::Substitute("SUT port '$0' was not found in control switch "
+                         "to control switch P4RT port ID map.",
+                         sut_port));
+  }
+  return it->first;
 }
 
 absl::Status CheckAndStoreMappedAndUnmappedPortIds(
diff --git a/dvaas/port_id_map.h b/dvaas/port_id_map.h
index 0246b5c0..38922d83 100644
--- a/dvaas/port_id_map.h
+++ b/dvaas/port_id_map.h
@@ -66,6 +66,12 @@ class MirrorTestbedP4rtPortIdMap {
   absl::StatusOr<pins_test::P4rtPortId> GetSutPortConnectedToControlSwitchPort(
       const pins_test::P4rtPortId& control_port) const;
 
+  // Returns the P4RT port ID of the control switch interface connected to the
+  // interface on the SUT with the given P4RT port ID according to the port
+  // mapping.
+  absl::StatusOr<pins_test::P4rtPortId> GetControlSwitchPortConnectedToSutPort(
+      const pins_test::P4rtPortId& sut_port) const;
+
  private:
   MirrorTestbedP4rtPortIdMap(
       absl::flat_hash_map<pins_test::P4rtPortId, pins_test::P4rtPortId>
diff --git a/dvaas/port_id_map_test.cc b/dvaas/port_id_map_test.cc
index 8d023d53..3e265b9f 100644
--- a/dvaas/port_id_map_test.cc
+++ b/dvaas/port_id_map_test.cc
@@ -43,10 +43,17 @@ TEST(MirrorTestbedP4rtPortIdMap,
       MirrorTestbedP4rtPortIdMap::CreateFromControlSwitchToSutPortMap(
           {{port_1, port_2}}));
 
+  // Control -> SUT.
   ASSERT_THAT(port_id_map.GetSutPortConnectedToControlSwitchPort(port_2),
               StatusIs(absl::StatusCode::kNotFound));
   ASSERT_THAT(port_id_map.GetSutPortConnectedToControlSwitchPort(port_3),
               StatusIs(absl::StatusCode::kNotFound));
+
+  // SUT -> Control.
+  ASSERT_THAT(port_id_map.GetControlSwitchPortConnectedToSutPort(port_1),
+              StatusIs(absl::StatusCode::kNotFound));
+  ASSERT_THAT(port_id_map.GetControlSwitchPortConnectedToSutPort(port_3),
+              StatusIs(absl::StatusCode::kNotFound));
 }
 
 TEST(MirrorTestbedP4rtPortIdMap,
@@ -79,10 +86,17 @@ TEST(MirrorTestbedP4rtPortIdMap,
       MirrorTestbedP4rtPortIdMap::CreateFromSutToControlSwitchPortMap(
           {{port_1, port_2}}));
 
+  // Control -> SUT.
   ASSERT_THAT(port_id_map.GetSutPortConnectedToControlSwitchPort(port_1),
               StatusIs(absl::StatusCode::kNotFound));
   ASSERT_THAT(port_id_map.GetSutPortConnectedToControlSwitchPort(port_3),
               StatusIs(absl::StatusCode::kNotFound));
+
+  // SUT -> Control.
+  ASSERT_THAT(port_id_map.GetControlSwitchPortConnectedToSutPort(port_2),
+              StatusIs(absl::StatusCode::kNotFound));
+  ASSERT_THAT(port_id_map.GetControlSwitchPortConnectedToSutPort(port_3),
+              StatusIs(absl::StatusCode::kNotFound));
 }
 
 TEST(MirrorTestbedP4rtPortIdMap,
@@ -101,32 +115,7 @@ TEST(MirrorTestbedP4rtPortIdMap,
               StatusIs(absl::StatusCode::kInvalidArgument));
 }
 
-TEST(MirrorTestbedP4rtPortIdMap,
-     RetrunsCorrectSutPortGivenControlPortGivenControlToSutMapping) {
-  ASSERT_OK_AND_ASSIGN(const auto port_1,
-                       P4rtPortId::MakeFromP4rtEncoding("1"));
-  ASSERT_OK_AND_ASSIGN(const auto port_2,
-                       P4rtPortId::MakeFromP4rtEncoding("2"));
-  ASSERT_OK_AND_ASSIGN(const auto port_3,
-                       P4rtPortId::MakeFromP4rtEncoding("3"));
-  ASSERT_OK_AND_ASSIGN(const auto port_4,
-                       P4rtPortId::MakeFromP4rtEncoding("4"));
-
-  ASSERT_OK_AND_ASSIGN(
-      const auto port_id_map,
-      MirrorTestbedP4rtPortIdMap::CreateFromControlSwitchToSutPortMap({
-          {port_1, port_2},
-          {port_3, port_4},
-      }));
-
-  ASSERT_THAT(port_id_map.GetSutPortConnectedToControlSwitchPort(port_1),
-              IsOkAndHolds(Eq(port_2)));
-  ASSERT_THAT(port_id_map.GetSutPortConnectedToControlSwitchPort(port_3),
-              IsOkAndHolds(Eq(port_4)));
-}
-
-TEST(MirrorTestbedP4rtPortIdMap,
-     RetrunsCorrectSutPortGivenControlPortGivenSutToControlMapping) {
+TEST(MirrorTestbedP4rtPortIdMap, ReturnsCorrectPortGivenSutToControlMapping) {
   ASSERT_OK_AND_ASSIGN(const auto port_1,
                        P4rtPortId::MakeFromP4rtEncoding("1"));
   ASSERT_OK_AND_ASSIGN(const auto port_2,
@@ -143,23 +132,37 @@ TEST(MirrorTestbedP4rtPortIdMap,
           {port_3, port_4},
       }));
 
+  // Control -> SUT.
   ASSERT_THAT(port_id_map.GetSutPortConnectedToControlSwitchPort(port_2),
               IsOkAndHolds(Eq(port_1)));
   ASSERT_THAT(port_id_map.GetSutPortConnectedToControlSwitchPort(port_4),
               IsOkAndHolds(Eq(port_3)));
+
+  // SUT -> Control.
+  ASSERT_THAT(port_id_map.GetControlSwitchPortConnectedToSutPort(port_1),
+              IsOkAndHolds(Eq(port_2)));
+  ASSERT_THAT(port_id_map.GetControlSwitchPortConnectedToSutPort(port_3),
+              IsOkAndHolds(Eq(port_4)));
 }
 
-TEST(MirrorTestbedP4rtPortIdMap, RetrunsCorrectSutPortWithImplicitIdentityMap) {
+TEST(MirrorTestbedP4rtPortIdMap, ReturnsCorrectPortWithImplicitIdentityMap) {
   const auto port_id_map = MirrorTestbedP4rtPortIdMap::CreateIdentityMap();
   ASSERT_OK_AND_ASSIGN(const auto port_1,
                        P4rtPortId::MakeFromP4rtEncoding("1"));
   ASSERT_OK_AND_ASSIGN(const auto port_2,
                        P4rtPortId::MakeFromP4rtEncoding("2"));
 
+  // Control -> SUT.
   ASSERT_THAT(port_id_map.GetSutPortConnectedToControlSwitchPort(port_1),
               IsOkAndHolds(Eq(port_1)));
   ASSERT_THAT(port_id_map.GetSutPortConnectedToControlSwitchPort(port_2),
               IsOkAndHolds(Eq(port_2)));
+
+  // SUT -> Control.
+  ASSERT_THAT(port_id_map.GetControlSwitchPortConnectedToSutPort(port_1),
+              IsOkAndHolds(Eq(port_1)));
+  ASSERT_THAT(port_id_map.GetControlSwitchPortConnectedToSutPort(port_2),
+              IsOkAndHolds(Eq(port_2)));
 }
 
 }  // namespace