There are several synonyms for the phrase "was behind" that can be used to express a similar meaning. For instance, "lagged behind" generally refers to falling behind in a race or competition. Another useful synonym is "trailed behind," which indicates following someone or something at a distance. Additionally, "was slower than" can be used when one person or team is slower than the other, indicating that they are "behind" in terms of progress or achievement. "Fell behind" is another commonly used phrase that suggests someone or something has become left behind or has lost ground and is now in a disadvantaged position compared to the competition.