The American has enjoyed a good first season in the Premier League with the London club.
But he struggled earlier in the season, often out of the starting line up.
Pulisic has recently shown his quality, scoring three goals and winning two penalties since the restart.
"I had that first game on my mind," he told Sky Sports after he was asked about his lockdown preparations.
"I was really hungry the whole time to get back and get back on the field. I was training hard and I'm really happy now to be able to make an impact.
"I was able to get some work in back in the States, as well, and be able to continue to work on my game but also rehabbing and making sure I was 100 per cent fit and ready to go.
"So during a really tough time for a lot of people, that was the one positive thing that I could do for myself."