Challenge Matches in Rivals -- how they work

As a new player in Rivals, you will quickly get so-called "Challenge Matches" on ladder. How do they work, and why do they exist?

What are the advantages of a Challenge Match?

• You cannot lose medals in the game
• You get extra experience points for the game, which accelerates your progress

What are the downsides of a Challenge Match?

• The downside is that as a new player, you will play a ton of Challenge Matches
• Medal-wise, each Challenge Match is a "freeroll", i.e. you cannot lose matches
• That's why you will climb the ladder up even if you have just 10% winrate in Challenge Matches
• This means that the system can mean that you actually get ever harder opponents because you get so many Challenge Matches, which can make the experience even more frustrating
• A good change would in my view be to keep XP bonus for Challenge Matches (maybe increase it), but to remove the medal impact of them

What triggers a Challenge Match?

One of the following conditions have to be met:

1. The opponent has a unit or commander in their deck that you have not unlocked yet. As a new player, you need to gradually unlock all units by levelling up to level 60. This takes some time, but costs no money. Until then, you will meet players that have units in their deck that you don't have unlocked, yet. This is hard for you because you often don't understand the unit well.
2. The opponent has more than 200 medals more than you, and you're not yet in Tiberium league. Medals are the ranking points of the Rivals "ranked" ladder. If a player is much higher than you, he likely is stronger (which is a compound of their skill and their potentially higher unit levels). 
3. The opponent's average deck level is at least 1.5 levels above your deck's average level. This is actually a bit complicated and causes most confusion, so some more details here:
• Average deck is calculated by summing up the levels of the 6 units and the commander, and dividing by 7. The "training" upgrades next to the levels do not count.
• Omar has (14 + 14 + 15 + 15 + 15 + 15 + 14) / 7 = 102 / 7 = 14.57
• s9a7d4 has (12 + 14 + 13 + 14 + 12 + 12 + 11) / 7 = 88 / 7 = 12.57
• There are actually two conditions that have to be met:
• The level difference must be 1.5 or higher
• The lower-levelled players' deck must be within 4 levels of the league cap (e.g. 13 for Masters -> you only get Challenge Matches if you're level 9 or higher)
• In the example below, the level difference is >1.5, and s9a7d4 is within 4 levels of the league cap (which is 15 for Tiberium), so the match is a challenge match.

Other "Rivals basics" articles for beginners:

• Basic deck construction guide for Rivals
• How to level up your units fast
• How much it cards and credits you need to upgrade your units to a certain level
• How the Tiberium income acceleration works throughout the game
• How to deal with Nod Scarabs?

Video recommendation: Watch the "Micro Queen" AliciaDestiny play.