Dodoo, 26, who recently signed a two-year deal after the club were allowed to bring in a free agent to boost their depleted options up front, hit both goals in Rovers' 2-1 group victory at the Keepmoat Stadium.
It followed on from the precious weekend League One success over Morecambe, Doncaster's maiden three points of the season and first on home soil since early March.
Wellens said: "It is good for his (Dodoo's) confidence. I would have liked Jordy (Hiwula) and Tiago to have got one. I think there were opportunities for them to score.
"But I think their all-round game, application, sharpness and brightness was all there. It was probably just a goal lacking from those two.
"Obviously, Joe getting the two goals (means) he should be full of confidence now and he has kick-started his career here.
"I think he brings loads of other attributes other than his goalscoring; his physique, power and work-rate as well. All three of them can be really pleased with their night's work.
"We are waiting for Fejiri (Okenabirhie) to come back and at the moment, instead of having to share the load with somebody, Joe is going to have to that mantle on himself to take the majority of the load, but also Tiago come in and was fantastic.
"He can take a lot of satisfaction from that and it was probably the best he has played for the club and he looked a lot fitter and sharper and kept going for ninety minutes.
Meanwhile, Wellens has revealed that midfielder John Bostock is to undergo a scan on an ankle issue which forced him off against City and he could be out for a couple of weeks.
Wellens, whose side now face back-to-back away league games at Plymouth Argyle and Ipswich Town, said: "John has got a problem with his ankle.
"We have not scanned it yet as he did not train today (Wednesday) as he obviously had to come off in a game, so we will know more when it is scanned.
"It is just a knock. We don't think it is anything serious and we think, worst-case, it might be one or two weeks, so it is not something we are overly concerned about."