diff --git a/.taskcluster.yml b/.taskcluster.yml
index eb3eff9b1f130de..1b803bb81508216 100644
--- a/.taskcluster.yml
+++ b/.taskcluster.yml
@@ -72,23 +72,14 @@ tasks:
                       ${event.after}
                       ${browser.name}-${browser.channel};
                     cd ~/web-platform-tests;
-                    ./wpt manifest-download || true;
                     ./tools/ci/taskcluster-run.py
-                      --browser ${browser.name}
+                      ${browser.name}
                       --
-                      --log-tbpl=../artifacts/log_tbpl.log
-                      --log-tbpl-level=info
                       --log-wptreport=../artifacts/wpt_report.json
-                      --log-mach=-
-                      -y
-                      --no-pause
-                      --no-restart-on-unexpected
-                      --install-fonts
                       --no-fail-on-unexpected
                       --test-type=${chunk[0]}
                       --this-chunk=${chunk[1]}
                       --total-chunks=${chunk[2]};
-                    gzip ../artifacts/wpt_report.json;
     - $if: tasks_for == "github-pull-request"
       then:
         $map: [{name: firefox, channel: nightly}, {name: chrome, channel: dev}]
@@ -137,24 +128,15 @@ tasks:
                     ${event.pull_request.base.sha}
                     ${browser.name}-${browser.channel};
                   cd ~/web-platform-tests;
-                  ./wpt manifest-download || true;
                   git fetch
                     ${event.repository.clone_url}
                     refs/pull/${event.number}/head;
                   git checkout FETCH_HEAD;
                   result=0;
                   ./tools/ci/taskcluster-run.py
-                    --browser ${browser.name}
                     --commit-range ${event.pull_request.base.sha}...
+                    ${browser.name}
                     --
-                    ${command.extra_args}
-                    --log-tbpl=../artifacts/log_tbpl.log
-                    --log-tbpl-level=info
-                    --log-mach=-
-                    -y
-                    --no-pause
-                    --no-restart-on-unexpected
-                     --install-fonts || result=$?;
-                  if [ -f ../artifacts/wpt_report.json ]; then gzip ../artifacts/wpt_report.json; fi;
+                    ${command.extra_args} || result=$?;
                   echo $result > ../artifacts/run-return-code.txt;
                   echo Command exited with code $result (failures are allowed while this task is being vetted).
diff --git a/tools/ci/taskcluster-run.py b/tools/ci/taskcluster-run.py
index 0bf5236c7d8a4b2..22909cc13db2dcb 100755
--- a/tools/ci/taskcluster-run.py
+++ b/tools/ci/taskcluster-run.py
@@ -1,8 +1,10 @@
 #!/usr/bin/env python
 
 import argparse
+import gzip
 import logging
 import os
+import shutil
 import subprocess
 
 browser_specific_args = {
@@ -23,7 +25,19 @@ def tests_affected(commit_range):
     return tests
 
 
-def main(browser, commit_range, wpt_args):
+def find_wptreport(args):
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--log-wptreport', action='store')
+    return parser.parse_known_args(args)[0].log_wptreport
+
+
+def gzip_file(filename):
+    with open(filename, 'rb') as f_in:
+        with gzip.open('%s.gz' % filename, 'wb') as f_out:
+            shutil.copyfileobj(f_in, f_out)
+
+
+def main(product, commit_range, wpt_args):
     """Invoke the `wpt run` command according to the needs of the TaskCluster
     continuous integration service."""
 
@@ -35,6 +49,9 @@ def main(browser, commit_range, wpt_args):
     )
     logger.addHandler(handler)
 
+    child = subprocess.Popen(['python', './wpt', 'manifest-download'])
+    child.wait()
+
     if commit_range:
         logger.info(
             "Identifying tests affected in range '%s'..." % commit_range
@@ -49,21 +66,36 @@ def main(browser, commit_range, wpt_args):
         tests = []
         logger.info("Running all tests")
 
-    wpt_args += browser_specific_args.get(browser, [])
+    wpt_args += [
+        "--log-tbpl=../artifacts/log_tbpl.log",
+        "--log-tbpl-level=info",
+        "--log-mach=-",
+        "-y",
+        "--no-pause",
+        "--no-restart-on-unexpected",
+        "--install-fonts"
+    ]
+    wpt_args += browser_specific_args.get(product, [])
 
-    command = ["python", "./wpt", "run"] + wpt_args + [browser] + tests
+    command = ["python", "./wpt", "run"] + wpt_args + [product] + tests
 
     logger.info("Executing command: %s" % " ".join(command))
 
     subprocess.check_call(command)
 
+    wptreport = find_wptreport(wpt_args)
+    if wptreport:
+        gzip_file(wptreport)
+
 
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(description=main.__doc__)
-    parser.add_argument("--browser", action="store", required=True)
     parser.add_argument("--commit-range", action="store",
                         help="""Git commit range. If specified, this will be
                              supplied to the `wpt tests-affected` command to
-                             determine the list of tests executed""")
-    parser.add_argument("wpt_args", nargs="*")
+                             determine the list of test to execute""")
+    parser.add_argument("product", action="store",
+                        help="Browser to run tests in")
+    parser.add_argument("wpt_args", nargs="*",
+                        help="Arguments to forward to `wpt run` command")
     main(**vars(parser.parse_args()))