diff --git a/.circleci/config.yml b/.circleci/config.yml
index e4cf7abe..9f3680f5 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -61,9 +61,6 @@ jobs:
     environment:
       JASMINE_LONG_PROPERTY_TESTS: y
 
-  # Warning: Currently this is very flaky if anything else is using Sauce
-  # at the same time, possibly because we're not specifying the tunnel ID
-  # correctly. Probably not a good idea to run it from anything but a nightly.
   test_browsers:
     executor: node14
     steps:
@@ -85,6 +82,7 @@ jobs:
             # cleanly if we kill it from a different step than it started in.
 
             export PATH=$PATH:$HOME/workspace/bin
+            export SAUCE_TUNNEL_IDENTIFIER=$CIRCLE_BUILD_NUM
             scripts/start-sauce-connect sauce-pidfile
             set +o errexit
             scripts/run-all-browsers
diff --git a/scripts/start-sauce-connect b/scripts/start-sauce-connect
index b2679c9a..cfe551b2 100755
--- a/scripts/start-sauce-connect
+++ b/scripts/start-sauce-connect
@@ -15,7 +15,11 @@ fi
 
 outfile=`mktemp`
 echo "Starting Sauce Connect"
-sc -u "$SAUCE_USERNAME" -k "$SAUCE_ACCESS_KEY" -X 4445 --pidfile "$pidfile" 2>&1 | tee "$outfile" &
+if [ -z "$SAUCE_TUNNEL_IDENTIFIER" ]; then
+	sc -u "$SAUCE_USERNAME" -k "$SAUCE_ACCESS_KEY" -X 4445 --pidfile "$pidfile" 2>&1 | tee "$outfile" &
+else
+	sc -u "$SAUCE_USERNAME" -k "$SAUCE_ACCESS_KEY" -X 4445 --pidfile "$pidfile" -i "$SAUCE_TUNNEL_IDENTIFIER" 2>&1 | tee "$outfile" &
+fi
 
 while ! fgrep "Sauce Connect is up, you may start your tests." "$outfile" > /dev/null; do
     sleep 1
diff --git a/spec/support/jasmine-browser.js b/spec/support/jasmine-browser.js
index cacf28f7..8fd2ebad 100644
--- a/spec/support/jasmine-browser.js
+++ b/spec/support/jasmine-browser.js
@@ -42,9 +42,7 @@ module.exports = {
       browserVersion: process.env.SAUCE_BROWSER_VERSION,
       build: `Core ${process.env.TRAVIS_BUILD_NUMBER || 'Ran locally'}`,
       tags: ['Jasmine-Core'],
-      tunnelIdentifier: process.env.TRAVIS_JOB_NUMBER
-        ? process.env.TRAVIS_JOB_NUMBER.toString()
-        : null,
+      tunnelIdentifier: process.env.SAUCE_TUNNEL_IDENTIFIER,
       username: process.env.SAUCE_USERNAME,
       accessKey: process.env.SAUCE_ACCESS_KEY
     }