The Addicks needed a goal from Paul Benson to secure a point after Wayne Brown lashed the visitors into the lead. But once they had equalised, Parkinson's side were frustrated by Andersen who pulled off fine saves to deny Alan McCormack and Akpo Sodje late on.
"I thought we had enough chances to win the game and their keeper pulled off some good saves, we came up against a keeper on top form," shrugged Parkinson. "In terms of how many games we've had of late I couldn't have asked any more of the lads in terms of performance."
Charlton remain in second place despite their run of five straight wins coming to a halt, but Parkinson admits a tough schedule is taking its toll.
"It's a bit of a walking wounded in the dressing room at the moment," he added. "Gary Doherty has a dead leg and Jose Semedo has a strain at the top of his hamstring so we're going to have to piece together a team for Saturday.
"But we've played a lot of games and it's been a really tough month, we've come through it very well."
Source: PA
Source: PA