From an early start in coaching, I was 'taught' that it's best to give your players the best chance for success. This means that favoring your topic focus would mean success and it should translate to success in the game at the weekend. For example, 2v1 would favor the two players. If I wanted to work on through balls and combination play, I could set up a 2v1 which would present lots of opportunities to combine or to play through balls. It would be ideal for training a single striker. A simple overload for success.
What about an underload?
Take the title. 1v2. It doesn't also need to be trained like a typical 1v1, so that the one can beat the two. In my book (1v1's Outside the Box), I talk about analyzing the situation you are recreating and if it's accurate. What does your striker do, when receiving the ball with two defenders on their back? What do you want them to do?
This is the cover image and shows a long ball that has been played into an isolated striker against two defenders.
Now, subjectively you can assess the scenario and be able to recreate this in training (if this is a trend, of course).
How do you train this?
Option A - A long ball into a 1v2, with the expectation that the #9 can beat the #2 and #4 to score a goal. Maybe you have a goalkeeper. You might allow the ball to go back to the #8 for a give-and-go or for some type of supporting pass.
What about option B -
Divide the field into two-thirds. one-third (attacking third) for an isolated striker to receive the ball. Another two-thirds for a 4v2 (or variation thereof). To attack the goal, the blue must play the ball into the attacking third first. Here we recreate the 1v2, but we're also training the behavior around and underneath to support the isolated striker. Which, for me, is what I want to happen in a game. The three players circled are vitally important to this scenario and success in a game, so they become as much of a focus, as the isolated striker.
Option C - What would you do?