diff --git a/src/PhpSpreadsheet/Worksheet/AutoFilter.php b/src/PhpSpreadsheet/Worksheet/AutoFilter.php
index 05b2e9a0..d6041985 100644
--- a/src/PhpSpreadsheet/Worksheet/AutoFilter.php
+++ b/src/PhpSpreadsheet/Worksheet/AutoFilter.php
@@ -9,7 +9,7 @@ use PhpOffice\PhpSpreadsheet\Calculation\Functions;
 use PhpOffice\PhpSpreadsheet\Calculation\Internal\WildcardMatch;
 use PhpOffice\PhpSpreadsheet\Cell\AddressRange;
 use PhpOffice\PhpSpreadsheet\Cell\Coordinate;
-use PhpOffice\PhpSpreadsheet\Exception as PhpSpreadsheetException;
+use PhpOffice\PhpSpreadsheet\Exception;
 use PhpOffice\PhpSpreadsheet\Shared\Date;
 use PhpOffice\PhpSpreadsheet\Worksheet\AutoFilter\Column\Rule;
 
@@ -104,7 +104,7 @@ class AutoFilter
      * Set AutoFilter Cell Range.
      *
      * @param AddressRange|array<int>|string $range
-     *            A simple string containing a Cell range like 'A1:E10' is permitted
+     *            A simple string containing a Cell range like 'A1:E10' or a Cell address like 'A1' is permitted
      *              or passing in an array of [$fromColumnIndex, $fromRow, $toColumnIndex, $toRow] (e.g. [3, 5, 6, 8]),
      *              or an AddressRange object.
      */
@@ -115,6 +115,7 @@ class AutoFilter
         if ($range !== '') {
             [, $range] = Worksheet::extractSheetTitle(Validations::validateCellRange($range), true);
         }
+
         if (empty($range)) {
             //    Discard all column rules
             $this->columns = [];
@@ -123,8 +124,8 @@ class AutoFilter
             return $this;
         }
 
-        if (strpos($range, ':') === false) {
-            throw new PhpSpreadsheetException('Autofilter must be set on a range of cells.');
+        if (ctype_digit($range) || ctype_alpha($range)) {
+            throw new Exception("{$range} is an invalid range for AutoFilter");
         }
 
         $this->range = $range;
@@ -174,13 +175,13 @@ class AutoFilter
     public function testColumnInRange($column)
     {
         if (empty($this->range)) {
-            throw new PhpSpreadsheetException('No autofilter range is defined.');
+            throw new Exception('No autofilter range is defined.');
         }
 
         $columnIndex = Coordinate::columnIndexFromString($column);
         [$rangeStart, $rangeEnd] = Coordinate::rangeBoundaries($this->range);
         if (($rangeStart[0] > $columnIndex) || ($rangeEnd[0] < $columnIndex)) {
-            throw new PhpSpreadsheetException('Column is outside of current autofilter range.');
+            throw new Exception('Column is outside of current autofilter range.');
         }
 
         return $columnIndex - $rangeStart[0];
@@ -247,7 +248,7 @@ class AutoFilter
         } elseif (is_object($columnObjectOrString) && ($columnObjectOrString instanceof AutoFilter\Column)) {
             $column = $columnObjectOrString->getColumnIndex();
         } else {
-            throw new PhpSpreadsheetException('Column is not within the autofilter range.');
+            throw new Exception('Column is not within the autofilter range.');
         }
         $this->testColumnInRange($column);
 
@@ -1031,6 +1032,8 @@ class AutoFilter
             }
         }
 
+        $rangeEnd[1] = $this->autoExtendRange($rangeStart[1], $rangeEnd[1]);
+
         //    Execute the column tests for each row in the autoFilter range to determine show/hide,
         for ($row = $rangeStart[1] + 1; $row <= $rangeEnd[1]; ++$row) {
             $result = true;
@@ -1053,6 +1056,29 @@ class AutoFilter
         return $this;
     }
 
+    /**
+     * Magic Range Auto-sizing.
+     * For a single row rangeSet, we follow MS Excel rules, and search for the first empty row to determine our range.
+     */
+    public function autoExtendRange(int $startRow, int $endRow): int
+    {
+        if ($startRow === $endRow && $this->workSheet !== null) {
+            try {
+                $rowIterator = $this->workSheet->getRowIterator($startRow + 1);
+            } catch (Exception $e) {
+                // If there are no rows below $startRow
+                return $startRow;
+            }
+            foreach ($rowIterator as $row) {
+                if ($row->isEmpty(CellIterator::TREAT_NULL_VALUE_AS_EMPTY_CELL | CellIterator::TREAT_EMPTY_STRING_AS_EMPTY_CELL) === true) {
+                    return $row->getRowIndex() - 1;
+                }
+            }
+        }
+
+        return $endRow;
+    }
+
     /**
      * Implement PHP __clone to create a deep clone, not just a shallow copy.
      */
diff --git a/src/PhpSpreadsheet/Writer/Xlsx/DefinedNames.php b/src/PhpSpreadsheet/Writer/Xlsx/DefinedNames.php
index b3338c07..0ca9f64f 100644
--- a/src/PhpSpreadsheet/Writer/Xlsx/DefinedNames.php
+++ b/src/PhpSpreadsheet/Writer/Xlsx/DefinedNames.php
@@ -115,7 +115,9 @@ class DefinedNames
             [, $range[0]] = Worksheet::extractSheetTitle($range[0], true);
 
             $range[0] = Coordinate::absoluteCoordinate($range[0]);
-            $range[1] = Coordinate::absoluteCoordinate($range[1]);
+            if (count($range) > 1) {
+                $range[1] = Coordinate::absoluteCoordinate($range[1]);
+            }
             $range = implode(':', $range);
 
             $this->objWriter->writeRawData('\'' . str_replace("'", "''", $worksheet->getTitle()) . '\'!' . $range);
diff --git a/tests/PhpSpreadsheetTests/Worksheet/AutoFilter/AutoFilterTest.php b/tests/PhpSpreadsheetTests/Worksheet/AutoFilter/AutoFilterTest.php
index a80d3d63..ebec3686 100644
--- a/tests/PhpSpreadsheetTests/Worksheet/AutoFilter/AutoFilterTest.php
+++ b/tests/PhpSpreadsheetTests/Worksheet/AutoFilter/AutoFilterTest.php
@@ -65,6 +65,7 @@ class AutoFilterTest extends SetupTeardown
         $ranges = [
             'G1:J512' => "$title!G1:J512",
             'K1:N20' => 'K1:N20',
+            'B10' => 'B10',
         ];
 
         foreach ($ranges as $actualRange => $fullRange) {
@@ -94,11 +95,22 @@ class AutoFilterTest extends SetupTeardown
         self::assertEquals($expectedResult, $result);
     }
 
-    public function testSetRangeInvalidRange(): void
+    public function testSetRangeInvalidRowRange(): void
     {
         $this->expectException(PhpSpreadsheetException::class);
 
-        $expectedResult = 'A1';
+        $expectedResult = '999';
+
+        $sheet = $this->getSheet();
+        $autoFilter = $sheet->getAutoFilter();
+        $autoFilter->setRange($expectedResult);
+    }
+
+    public function testSetRangeInvalidColumnRange(): void
+    {
+        $this->expectException(PhpSpreadsheetException::class);
+
+        $expectedResult = 'ABC';
 
         $sheet = $this->getSheet();
         $autoFilter = $sheet->getAutoFilter();
@@ -498,4 +510,26 @@ class AutoFilterTest extends SetupTeardown
         self::assertArrayHasKey('K', $columns);
         self::assertArrayHasKey('M', $columns);
     }
+
+    public function testAutoExtendRange(): void
+    {
+        $spreadsheet = $this->getSpreadsheet();
+        $worksheet = $spreadsheet->addSheet(new Worksheet($spreadsheet, 'Autosized AutoFilter'));
+
+        $worksheet->getCell('A1')->setValue('Col 1');
+        $worksheet->getCell('B1')->setValue('Col 2');
+
+        $worksheet->setAutoFilter('A1:B1');
+        $lastRow = $worksheet->getAutoFilter()->autoExtendRange(1, 1);
+        self::assertSame(1, $lastRow, 'No data below AutoFilter, so there should ne no resize');
+
+        $lastRow = $worksheet->getAutoFilter()->autoExtendRange(1, 999);
+        self::assertSame(999, $lastRow, 'Filter range is already correctly sized');
+
+        $data = [['A', 'A'], ['B', 'A'], ['A', 'B'], ['C', 'B'], ['B', null], [null, null], ['D', 'D'], ['E', 'E']];
+        $worksheet->fromArray($data, null, 'A2', true);
+
+        $lastRow = $worksheet->getAutoFilter()->autoExtendRange(1, 1);
+        self::assertSame(6, $lastRow, 'Filter range has been re-sized incorrectly');
+    }
 }