diff --git a/jetty-http/src/main/java/org/eclipse/jetty/http/HttpField.java b/jetty-http/src/main/java/org/eclipse/jetty/http/HttpField.java
index db7bce9072b..e4b1aa18953 100644
--- a/jetty-http/src/main/java/org/eclipse/jetty/http/HttpField.java
+++ b/jetty-http/src/main/java/org/eclipse/jetty/http/HttpField.java
@@ -37,7 +37,14 @@ public class HttpField
     public HttpField(HttpHeader header, String name, String value)
     {
         _header = header;
-        _name = name;
+        if (_header != null && name == null)
+        {
+            _name = _header.asString();
+        }
+        else
+        {
+            _name = Objects.requireNonNull(name);
+        }
         _value = value;
     }
 
@@ -325,8 +332,6 @@ public class HttpField
             return false;
         if (!_name.equalsIgnoreCase(field.getName()))
             return false;
-        if (_value == null && field.getValue() != null)
-            return false;
         return Objects.equals(_value, field.getValue());
     }
 
diff --git a/jetty-http/src/test/java/org/eclipse/jetty/http/HttpFieldsTest.java b/jetty-http/src/test/java/org/eclipse/jetty/http/HttpFieldsTest.java
index bb8a71e4012..e911cbde5e1 100644
--- a/jetty-http/src/test/java/org/eclipse/jetty/http/HttpFieldsTest.java
+++ b/jetty-http/src/test/java/org/eclipse/jetty/http/HttpFieldsTest.java
@@ -30,6 +30,8 @@ import java.util.NoSuchElementException;
 import org.eclipse.jetty.util.BufferUtil;
 import org.hamcrest.Matchers;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.containsString;
@@ -666,6 +668,42 @@ public class HttpFieldsTest
         assertFalse(header.containsKey("n11"));
     }
 
+    @ParameterizedTest
+    @ValueSource(strings = {"Host", "host", "HOST", "HoSt", "Connection", "CONNECTION", "connection", "CoNnEcTiOn"})
+    public void testContainsKeyTrue(String keyName)
+    {
+        HttpFields fields = new HttpFields();
+        fields.put("Host", "localhost");
+        HttpField namelessField = new HttpField(HttpHeader.CONNECTION, null, "bogus");
+        fields.put(namelessField);
+
+        assertTrue(fields.containsKey(keyName), "containsKey('" + keyName + "')");
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {"Content-Type", "Content-Length", "X-Bogus", ""})
+    public void testContainsKeyFalse(String keyName)
+    {
+        HttpFields fields = new HttpFields();
+        fields.add("Host", "localhost");
+        HttpField namelessField = new HttpField(HttpHeader.CONNECTION, null, "bogus");
+        fields.put(namelessField);
+        System.out.println(fields);
+
+        assertFalse(fields.containsKey(keyName), "containsKey('" + keyName + "')");
+    }
+
+    @Test
+    public void testPreventNullField()
+    {
+        HttpFields fields = new HttpFields();
+        assertThrows(NullPointerException.class, () ->
+        {
+            HttpField nullNullField = new HttpField(null, null, "bogus");
+            fields.put(nullNullField);
+        });
+    }
+
     @Test
     public void testIteration() throws Exception
     {