Marinade roast for 8 hours in refrigerator
Remove from marinade
Sauté roast in oil for 4 minutes per side in instant pot
Pour marinade into instant pot
Add celery, onions, potatoes and carrots
Pressure Cook on High for 75 minutes for Medium Well (65 minutes for medium, 55 for medium rare)
Do a quick release
Remove roast, tent and rest for 5 - 10 minutes
Scoop out vegetables and strain liquid
Switch to sauté, add 2 Cups liquid back into instant pot
Add slurry
Cook to desired thickness
Slice roast
Serve roast sliced with vegetables and gravy