Pearce, Under-23s boss Kevin Nugent and player-coach Shaun Williams took charge of Millwall at Deepdale on Wednesday night because all the club's senior coaching personnel are currently in self-isolation.
Rowett's positive test was announced on Friday and he will also miss Saturday's home match against Huddersfield, while two further unnamed members of his coaching staff have since returned positive results.
Rowett watched Wednesday night's game from his London home, with a link to a pitchside phone, and second-half goals from Kenneth Zohore and Jed Wallace extended Millwall's unbeaten run to four matches as they moved into the Championship top six.
"The gaffer was right there behind them; he set everything up beforehand, and he's been in touch throughout the game, directing on tactics, asking opinions on substitutions and pretty much everything else," said Pearce.
"It's been a real eye-opener, a real experience for us, especially me and Willo [Williams].
"Nuge has got that experience, which is massive for me and Willo to lean on. The gaffer, at home via Zoom, has been great. He's really helped us, nurtured us through the last 48 hours.
"He's kept it really simple for me and Willo to go and articulate to the lads what he wants from them. We just relayed his message. He's been a really big influence over the last 48 hours, he's really calmed us and settled us down.
"As a player, you just worry about yourself. You're in your own bubble worrying about getting yourself physically and mentally through each game. But when you step into management, you go from yourself to thinking about everyone and the smallest thing that could potentially go wrong.
"It's probably mentally more tiring but I think the rewards are fantastic. We experienced that last night and hopefully we get another one on Saturday."
West Brom loanee Zohore marked his full debut with a tap in before Wallace added a late second from the penalty spot.
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