diff --git a/config/ompi_check_ucx.m4 b/config/ompi_check_ucx.m4
index 6994af8e51..62cb693bb9 100644
--- a/config/ompi_check_ucx.m4
+++ b/config/ompi_check_ucx.m4
@@ -100,6 +100,15 @@ AC_DEFUN([OMPI_CHECK_UCX],[
                                 AC_MSG_RESULT([$ompi_check_ucx_happy])
                                 CPPFLAGS=$old_CPPFLAGS])])
 
+                  old_CPPFLAGS="$CPPFLAGS"
+                  AS_IF([test -n "$ompi_check_ucx_dir"],
+                        [CPPFLAGS="$CPPFLAGS -I$ompi_check_ucx_dir/include"])
+                  AC_CHECK_DECLS([ucp_tag_send_nbr],
+                                 [AC_DEFINE([HAVE_UCP_TAG_SEND_NBR],[1],
+                                            [have ucp_tag_send_nbr()])], [],
+                                 [#include <ucp/api/ucp.h>])
+                  CPPFLAGS=$old_CPPFLAGS
+
                   OPAL_SUMMARY_ADD([[Transports]],[[Open UCX]],[$1],[$ompi_check_ucx_happy])])])
 
     AS_IF([test "$ompi_check_ucx_happy" = "yes"],
diff --git a/ompi/mca/pml/ucx/pml_ucx.c b/ompi/mca/pml/ucx/pml_ucx.c
index d7cac1b382..cf453dd1c5 100644
--- a/ompi/mca/pml/ucx/pml_ucx.c
+++ b/ompi/mca/pml/ucx/pml_ucx.c
@@ -75,6 +75,9 @@ mca_pml_ucx_module_t ompi_pml_ucx = {
     NULL    /* ucp_worker */
 };
 
+#define PML_UCX_REQ_ALLOCA() \
+    ((char *)alloca(ompi_pml_ucx.request_size) + ompi_pml_ucx.request_size);
+
 static int mca_pml_ucx_send_worker_address(void)
 {
     ucp_address_t *address;
@@ -525,7 +528,7 @@ int mca_pml_ucx_recv(void *buf, size_t count, ompi_datatype_t *datatype, int src
     PML_UCX_TRACE_RECV("%s", buf, count, datatype, src, tag, comm, "recv");
 
     PML_UCX_MAKE_RECV_TAG(ucp_tag, ucp_tag_mask, tag, src, comm);
-    req = (char *)alloca(ompi_pml_ucx.request_size) + ompi_pml_ucx.request_size;
+    req = PML_UCX_REQ_ALLOCA();
     status = ucp_tag_recv_nbr(ompi_pml_ucx.ucp_worker, buf, count,
                               mca_pml_ucx_get_datatype(datatype),
                               ucp_tag, ucp_tag_mask, req);
@@ -715,26 +718,18 @@ int mca_pml_ucx_isend(const void *buf, size_t count, ompi_datatype_t *datatype,
     }
 }
 
-int mca_pml_ucx_send(const void *buf, size_t count, ompi_datatype_t *datatype, int dst,
-                     int tag, mca_pml_base_send_mode_t mode,
-                     struct ompi_communicator_t* comm)
+static inline __opal_attribute_always_inline__ int
+mca_pml_ucx_send_nb(ucp_ep_h ep, const void *buf, size_t count,
+                    ompi_datatype_t *datatype, ucp_datatype_t ucx_datatype,
+                    ucp_tag_t tag, mca_pml_base_send_mode_t mode,
+                    ucp_send_callback_t cb)
 {
     ompi_request_t *req;
-    ucp_ep_h ep;
-
-    PML_UCX_TRACE_SEND("%s", buf, count, datatype, dst, tag, mode, comm, 
-                       mode == MCA_PML_BASE_SEND_BUFFERED ? "bsend" : "send");
-
-    ep = mca_pml_ucx_get_ep(comm, dst);
-    if (OPAL_UNLIKELY(NULL == ep)) {
-        PML_UCX_ERROR("Failed to get ep for rank %d", dst);
-        return OMPI_ERROR;
-    }
 
     req = (ompi_request_t*)mca_pml_ucx_common_send(ep, buf, count, datatype,
                                                    mca_pml_ucx_get_datatype(datatype),
-                                                   PML_UCX_MAKE_SEND_TAG(tag, comm),
-                                                   mode, mca_pml_ucx_send_completion);
+                                                   tag, mode,
+                                                   mca_pml_ucx_send_completion);
 
     if (OPAL_LIKELY(req == NULL)) {
         return OMPI_SUCCESS;
@@ -749,6 +744,60 @@ int mca_pml_ucx_send(const void *buf, size_t count, ompi_datatype_t *datatype, i
     }
 }
 
+#if HAVE_DECL_UCP_TAG_SEND_NBR
+static inline __opal_attribute_always_inline__ int
+mca_pml_ucx_send_nbr(ucp_ep_h ep, const void *buf, size_t count,
+                     ucp_datatype_t ucx_datatype, ucp_tag_t tag)
+
+{
+    void *req;
+    ucs_status_t status;
+
+    req    = PML_UCX_REQ_ALLOCA();
+    status = ucp_tag_send_nbr(ep, buf, count, ucx_datatype, tag, req);
+    if (OPAL_LIKELY(status == UCS_OK)) {
+        return OMPI_SUCCESS;
+    }
+
+    ucp_worker_progress(ompi_pml_ucx.ucp_worker);
+    while ((status = ucp_request_check_status(req)) == UCS_INPROGRESS) {
+        opal_progress();
+    }
+
+    return OPAL_LIKELY(UCS_OK == status) ? OMPI_SUCCESS : OMPI_ERROR;
+}
+#endif
+
+int mca_pml_ucx_send(const void *buf, size_t count, ompi_datatype_t *datatype, int dst,
+                     int tag, mca_pml_base_send_mode_t mode,
+                     struct ompi_communicator_t* comm)
+{
+    ucp_ep_h ep;
+
+    PML_UCX_TRACE_SEND("%s", buf, count, datatype, dst, tag, mode, comm,
+                       mode == MCA_PML_BASE_SEND_BUFFERED ? "bsend" : "send");
+
+    ep = mca_pml_ucx_get_ep(comm, dst);
+    if (OPAL_UNLIKELY(NULL == ep)) {
+        PML_UCX_ERROR("Failed to get ep for rank %d", dst);
+        return OMPI_ERROR;
+    }
+
+#if HAVE_DECL_UCP_TAG_SEND_NBR
+    if (OPAL_LIKELY((MCA_PML_BASE_SEND_BUFFERED != mode) &&
+                    (MCA_PML_BASE_SEND_SYNCHRONOUS != mode))) {
+        return mca_pml_ucx_send_nbr(ep, buf, count,
+                                    mca_pml_ucx_get_datatype(datatype),
+                                    PML_UCX_MAKE_SEND_TAG(tag, comm));
+    }
+#endif
+
+    return mca_pml_ucx_send_nb(ep, buf, count, datatype,
+                               mca_pml_ucx_get_datatype(datatype),
+                               PML_UCX_MAKE_SEND_TAG(tag, comm), mode,
+                               mca_pml_ucx_send_completion);
+}
+
 int mca_pml_ucx_iprobe(int src, int tag, struct ompi_communicator_t* comm,
                          int *matched, ompi_status_public_t* mpi_status)
 {