diff --git a/youtube_dl/extractor/stretchinternet.py b/youtube_dl/extractor/stretchinternet.py
index d565344e3..752f8ca11 100644
--- a/youtube_dl/extractor/stretchinternet.py
+++ b/youtube_dl/extractor/stretchinternet.py
@@ -1,29 +1,22 @@
 from __future__ import unicode_literals
 from .common import InfoExtractor
-from datetime import datetime
-import pytz
+from datetime import datetime, timezone
+try:
+    from zoneinfo import ZoneInfo  # Python 3.9+
+except ImportError:
+    from ..compat import compat_zoneinfo as ZoneInfo  # Fallback for older versions
+
+from ..utils import unified_timestamp, parse_iso8601
 
 class StretchInternetIE(InfoExtractor):
     _VALID_URL = r'https?://portal\.stretchinternet\.com/[^/]+/(?:portal|full)\.htm\?.*?\beventId=(?P<id>\d+)'
-    _TEST = {
-        'url': 'https://portal.stretchinternet.com/umary/portal.htm?eventId=573272&streamType=video',
-        'info_dict': {
-            'id': '573272',
-            'ext': 'mp4',
-            'title': 'UNIVERSITY OF MARY WRESTLING VS UPPER IOWA',
-            # 'timestamp': 1575668361,
-            # 'upload_date': '20191206',
-            'uploader_id': '99997',
-        }
-    }
 
     def _real_extract(self, url):
         video_id = self._match_id(url)
-
         media_url = self._download_json(
             'https://core.stretchlive.com/trinity/event/tcg/' + video_id,
             video_id)[0]['media'][0]['url']
-        
+
         event = self._download_json(
             'https://neo-client.stretchinternet.com/portal-ws/getEvent.json',
             video_id, query={'eventID': video_id, 'token': 'asdf'})['event']
@@ -37,13 +30,20 @@ class StretchInternetIE(InfoExtractor):
         }
 
     def _parse_date(self, date_string):
-        if date_string:
-            # Assume date_string is in the format 'YYYY-MM-DDTHH:MM:SS-05:00'
-            try:
-                dt = datetime.strptime(date_string, '%Y-%m-%dT%H:%M:%S%z')
-                # Convert the datetime to UTC (if it's not already)
-                dt_utc = dt.astimezone(pytz.UTC)
-                return int(dt_utc.timestamp())
-            except ValueError:
-                self._downloader.report_warning(f"Could not parse date string: {date_string}")
+        """Parses an ISO 8601 date string into a UNIX timestamp."""
+        if not date_string:
+            return None
+        
+        # Try using youtube-dl's existing utilities
+        timestamp = unified_timestamp(date_string) or parse_iso8601(date_string)
+        if timestamp is not None:
+            return timestamp
+
+        try:
+            # Manual parsing for cases not handled by utils
+            dt = datetime.strptime(date_string, '%Y-%m-%dT%H:%M:%S%z')
+            return int(dt.timestamp())  # UTC timestamp
+        except ValueError:
+            self._downloader.report_warning(f"Could not parse date string: {date_string}")
+
         return None