Consider the collection "things" for demonstration purposes, with 3 documents: db.things.insert({ "_id" : 'a' , arr: [{round:1, points:2000}, {round:2, points:1000}, {round:3, points:1000}]}); db.things.insert({ "_id" : 'b' , arr: [{round:1, points:1500}, {round:2, points:1500}, {round:3, points:3000}]}); db.things.insert({ "_id" : 'c' , arr: [{round:1, points:1000}, {round:2, points:2000}, {round:3, points:2000}]}); The query: db.things.find({ "arr.round" : 1}).sort({ "arr.points" : -1 }) returns the 3 documents in the following order: b, a, c However, if this index is created db.things.createIndex({ "arr.round" : 1, "arr.points" : -1}); The same query returns the documents in a different order (if index is used): a, b, c Nevertheless, If we want to always replicate this (second) sort behaviour with or without index, it can be done like this: db.things.find({ "arr" :{ "$elemMatch" : {round : 1}}}).sort({ "arr.$.points" : -1 })