diff --git a/src/FastExcelWriter/Sheet.php b/src/FastExcelWriter/Sheet.php
index 7e4557b..1c7275b 100644
--- a/src/FastExcelWriter/Sheet.php
+++ b/src/FastExcelWriter/Sheet.php
@@ -2509,7 +2509,7 @@ public function writeDataBegin(Writer $writer)
             return;
         }
 
-        $sheetFileName = $writer->makeTempFile('sheetData');
+        $sheetFileName = $writer->makeTempFile($this->index . ':sheetData');
         $this->setFileWriter($writer->makeFileWriter($sheetFileName));
 
         $this->fileWriter->write('<sheetData>');
diff --git a/src/FastExcelWriter/Writer/Writer.php b/src/FastExcelWriter/Writer/Writer.php
index 4f1d23d..92b0545 100644
--- a/src/FastExcelWriter/Writer/Writer.php
+++ b/src/FastExcelWriter/Writer/Writer.php
@@ -1036,7 +1036,7 @@ protected function _writeDrawingFile(string $entry, array $imageList, array $cha
      */
     protected function _writeSheetHead(Sheet $sheet): FileWriter
     {
-        $fileWriter = $this->makeFileWriter($this->makeTempFile('sheetHead'));
+        $fileWriter = $this->makeFileWriter($this->makeTempFile($sheet->index . ':sheetHead'));
         $fileWriter->write('<?xml version="1.0" encoding="UTF-8" standalone="yes"?>' . "\n");
         $nameSpaces = [
             'xmlns' => 'http://schemas.openxmlformats.org/spreadsheetml/2006/main',