diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RepositoryResolveTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RepositoryResolveTest.java
index 7f1dfc3..2773715 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RepositoryResolveTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RepositoryResolveTest.java
@@ -277,6 +277,7 @@ public void invalidNames() throws AmbiguousObjectException, IOException {
 		assertTrue(Repository.isValidRefName("x/a]b")); // odd, yes..
 		assertTrue(Repository.isValidRefName("x/\u00a0")); // unicode is fine,
 															// even hard space
+		assertFalse(Repository.isValidRefName("single-component"));
 		assertFalse(Repository.isValidRefName("x/.a"));
 		assertFalse(Repository.isValidRefName("x/a."));
 		assertFalse(Repository.isValidRefName("x/a..b"));
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/ReceivePackTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/ReceivePackTest.java
index 595b970..bcc7082 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/ReceivePackTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/ReceivePackTest.java
@@ -42,22 +42,57 @@
 
 package org.eclipse.jgit.transport;
 
+import java.util.ArrayList;
+
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.fail;
-
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
 import org.eclipse.jgit.errors.PackProtocolException;
 import org.eclipse.jgit.internal.JGitText;
+import org.eclipse.jgit.internal.storage.dfs.DfsRepositoryDescription;
+import org.eclipse.jgit.internal.storage.dfs.InMemoryRepository;
+import org.eclipse.jgit.junit.TestRepository;
+import org.eclipse.jgit.junit.TestRepository.BranchBuilder;
+import org.eclipse.jgit.lib.NullProgressMonitor;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.transport.ReceiveCommand.Result;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.junit.After;
+import org.junit.Before;
 import org.junit.Test;
 
 /** Tests for receive-pack utilities. */
 public class ReceivePackTest {
+	private URIish uri;
+	private TestProtocol<Object> testProtocol;
+	private InMemoryRepository client;
+	private InMemoryRepository server;
+	private TestRepository clientTestRepo;
+	private TestRepository serverTestRepo;
+
+	@Before
+	public void setUp() throws Exception {
+		client = new InMemoryRepository(new DfsRepositoryDescription("client"));
+		server = new InMemoryRepository(new DfsRepositoryDescription("server"));
+		clientTestRepo = new TestRepository<>(client);
+		serverTestRepo = new TestRepository<>(server);
+
+		testProtocol = new TestProtocol<>(null, (Object req, Repository db) -> {
+			ReceivePack rp = new ReceivePack(db);
+			return rp;
+		});
+		uri = testProtocol.register(new Object(), server);
+	}
+
+	@After
+	public void tearDown() {
+		Transport.unregister(testProtocol);
+	}
+
 	@Test
 	public void parseCommand() throws Exception {
 		String o = "0000000000000000000000000000000000000000";
@@ -81,6 +116,54 @@ public void parseCommand() throws Exception {
 		assertParseCommandFails(o + " " + "X" + n.substring(1) + " " + r);
 	}
 
+	/**
+	 * Ensure receive-pack rejects a push to a one level ref (refs/master).
+	 */
+	@Test
+	public void rejectsCreationOfOneLevelRef() throws Exception {
+		// Create refs/master on the client so we can attempt to push it
+		RevCommit clientCommit;
+		BranchBuilder bb = clientTestRepo.branch("refs/master");
+		clientCommit = bb.commit().noFiles().message("Testing").create();
+
+		ArrayList<RemoteRefUpdate> refUpdates = new ArrayList<>();
+		refUpdates.add(new RemoteRefUpdate(
+				clientTestRepo.getRepository(), "refs/master", clientCommit,
+				"refs/master", false, /* force update */
+				null, /* no local tracking ref */
+				ObjectId.zeroId() // expected advertisement
+		));
+		Transport tn = testProtocol.open(uri, client, "server");
+		PushResult result = tn.push(NullProgressMonitor.INSTANCE, refUpdates);
+		RemoteRefUpdate update = result.getRemoteUpdate("refs/master");
+
+		assertEquals(RemoteRefUpdate.Status.REJECTED_OTHER_REASON,
+				update.getStatus());
+		assertEquals(JGitText.get().funnyRefname, update.getMessage());
+	}
+
+	/**
+	 * Allow deletion of one level refs (refs/master).
+	 */
+	@Test
+	public void acceptsDeletionOfOneLevelRef() throws Exception {
+		BranchBuilder bb = serverTestRepo.branch("refs/master");
+		bb.update(bb.commit().noFiles().message("Testing").create());
+
+		ArrayList<RemoteRefUpdate> refUpdates = new ArrayList<>();
+		refUpdates.add(new RemoteRefUpdate(null, null, ObjectId.zeroId(),
+				"refs/master", false, // force update
+				null, // no local tracking ref
+				null // expected advertisement
+		));
+		Transport tn = testProtocol.open(uri, client, "server");
+		PushResult result = tn.push(NullProgressMonitor.INSTANCE, refUpdates);
+		RemoteRefUpdate update = result.getRemoteUpdate("refs/master");
+
+		assertEquals(RemoteRefUpdate.Status.OK, update.getStatus());
+		assertEquals(null, update.getMessage());
+	}
+
 	private void assertParseCommandFails(String input) {
 		try {
 			ReceivePack.parseCommand(input);
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java
index c9dc6da..01a4361 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java
@@ -1375,6 +1375,8 @@ public RepositoryState getRepositoryState() {
 	 *
 	 * For portability reasons '\' is excluded
 	 *
+	 * @see <a href="http://www.kernel.org/pub/software/scm/git/docs/git-check-ref-format.html"
+	 *      >git-check-ref-format(1) manual page</a>
 	 * @param refName a {@link java.lang.String} object.
 	 * @return true if refName is a valid ref name
 	 */
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/ReceivePack.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/ReceivePack.java
index 8b05d41..ec7d4c1 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/ReceivePack.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/ReceivePack.java
@@ -1658,6 +1658,18 @@ private void validateCommands() {
 					continue;
 				}
 
+				if (cmd.getRefName().startsWith(Constants.R_REFS)
+					&& !Repository.isValidRefName(
+						cmd.getRefName().substring(Constants.R_REFS.length())
+					)
+				) {
+					// Reject the creation of one level references such as
+					// refs/master to match cgit implementation.
+					cmd.setResult(Result.REJECTED_OTHER_REASON,
+							JGitText.get().funnyRefname);
+					continue;
+				}
+
 				if (ref != null) {
 					// A well behaved client shouldn't have sent us a
 					// create command for a ref we advertised to it.
@@ -1753,8 +1765,18 @@ private void validateCommands() {
 				}
 			}
 
-			if (!cmd.getRefName().startsWith(Constants.R_REFS)
-					|| !Repository.isValidRefName(cmd.getRefName())) {
+			if (!cmd.getRefName().startsWith(Constants.R_REFS)) {
+				cmd.setResult(Result.REJECTED_OTHER_REASON,
+						JGitText.get().funnyRefname);
+			}
+
+			if (!Repository.isValidRefName(cmd.getRefName())
+				// But accept deletion of one level refs (refs/main)
+				&& !(
+					cmd.getType() == ReceiveCommand.Type.DELETE
+					&& Repository.isValidRefName(cmd.getRefName().substring(Constants.R_REFS.length()))
+				)
+			) {
 				cmd.setResult(Result.REJECTED_OTHER_REASON,
 						JGitText.get().funnyRefname);
 			}