diff --git a/src/GitVersion.Core.Tests/VersionCalculation/SemanticVersionTests.cs b/src/GitVersion.Core.Tests/VersionCalculation/SemanticVersionTests.cs
index cba8885aab..1637227ffd 100644
--- a/src/GitVersion.Core.Tests/VersionCalculation/SemanticVersionTests.cs
+++ b/src/GitVersion.Core.Tests/VersionCalculation/SemanticVersionTests.cs
@@ -34,6 +34,8 @@ public class SemanticVersionTests : TestBase
         [TestCase("v1.2.3", 1, 2, 3, null, null, null, null, null, null, "1.2.3", Config.DefaultTagPrefix)]
         [TestCase("V1.2.3", 1, 2, 3, null, null, null, null, null, null, "1.2.3", Config.DefaultTagPrefix)]
         [TestCase("version-1.2.3", 1, 2, 3, null, null, null, null, null, null, "1.2.3", "version-")]
+        [TestCase("1", 1, 0, 0, null, null, null, null, null, null, "1.0.0", null)]
+        [TestCase("1.1", 1, 1, 0, null, null, null, null, null, null, "1.1.0", null)]
         public void ValidateVersionParsing(
             string versionString, int major, int minor, int patch, string tag, int? tagNumber, int? numberOfBuilds,
             string branchName, string sha, string otherMetaData, string fullFormattedVersionString, string tagPrefixRegex)
diff --git a/src/GitVersion.Core/VersionCalculation/SemanticVersioning/SemanticVersion.cs b/src/GitVersion.Core/VersionCalculation/SemanticVersioning/SemanticVersion.cs
index 65494749ed..3975a634f8 100644
--- a/src/GitVersion.Core/VersionCalculation/SemanticVersioning/SemanticVersion.cs
+++ b/src/GitVersion.Core/VersionCalculation/SemanticVersioning/SemanticVersion.cs
@@ -8,7 +8,7 @@ public class SemanticVersion : IFormattable, IComparable<SemanticVersion>
         private static SemanticVersion Empty = new SemanticVersion();
 
         private static readonly Regex ParseSemVer = new Regex(
-            @"^(?<SemVer>(?<Major>\d+)(\.(?<Minor>\d+))(\.(?<Patch>\d+))?)(\.(?<FourthPart>\d+))?(-(?<Tag>[^\+]*))?(\+(?<BuildMetaData>.*))?$",
+            @"^(?<SemVer>(?<Major>\d+)?(\.(?<Minor>\d+))?(\.(?<Patch>\d+))?)(\.(?<FourthPart>\d+))?(-(?<Tag>[^\+]*))?(\+(?<BuildMetaData>.*))?$",
             RegexOptions.Compiled);
 
         public int Major;