The strikers formed a fine alliance during the 2012/13 campaign and both quickly reached double figures earlier this term, but they have barely played together over the winter due to injury. However, both men have featured in United's last five matches.
Speaking on the eve of United's first leg encounter with Olympiacos, Reds boss Moyes explained why their form is absolutely central to his hopes of European glory.
"They're both vital to a lot of the things we do," the boss told reporters during a press conference at the Karaiskakis Stadium in Athens. "They're both excellent players. Our record with them is far better than our record without them, that's for sure.
"Both have had injuries, Robin much longer than Wayne, and both have got themselves back into shape. They're both goalscorers and they're scoring goals, which is great for us. That's why they're top players – they score in big games and make the big moments."
After discussing why he won't be happy until winning a second Champions League winners' medal, Rooney echoed a similar sentiment to his manager and praised his Dutch team-mate van Persie.
"Robin's a fantastic player, one of the best goalscorers in world football. As the manager said, we have a good record when we play together. Unfortunately we had injuries at a