The Frenchman had to undergo a liver transplant in 2012, while the coach underwent surgery last month after a cancer relapse, and the 25-year-old has claimed that these events put things in perspective for the Catalans.
"To be honest, they [Vilanova and Abidal's health problems] hit us hard. It seemed like it was one thing after another, and they’re things that count much more than results or form," Messi told FIFA.com.
He added, "They’re really awful situations. Of course we were hit hard, but we somehow managed to get through all of that by sticking together throughout.
"And thank God things began looking up for both Abidal and Tito. Though he [Vilanova] has still got to keep us his treatment, all the signs are good. That’s what matters most."
The prolific attacker then went on to explain how things have changed for him with Argentina's national side over the course of 2012.
"The national team changed. For things to go well it depends on everybody involved, not just one player. And it’s not as if things were only going badly for me before, things weren't right with the national team as a whole, for whatever reason," Messi explained.
"But once we started winning and our results improved, everything got easier. The fans are behind us, the press aren't as critical as they have been in the past and we’re able to get on with the job in a different, calmer way.
"On top of that you end up getting more respect from opponents because of the form you’re in. The biggest change was the results, simple as that."
Messi netted 12 times for Argentina in 2012.