Villa began their pre-season with a 3-1 win over Mansfield and Lambert insists the striker can force his way into the first team next season.
Alan Hutton and Bent - both appearing for the club for the first time in over a year - combined to draw Villa level while Gary Gardner was also on the scoresheet.
“I’ve always known they have been good players,” said Lambert. “Everybody knows the situation that was going on with the football club but these lads have been brilliant.
“We’ve still got big players to come back as well – Benteke, Kozak, Vlaar, Guzan and Senderos. You can see there were a lot of positives from that game.
“There were a lot of positives out there with Jores Okore coming back after eight months out and also Charles N'Zogbia playing after a similar time away.
“There was also Gary Gardner and Chris Herd, so there were quite a few players who haven’t played for a long time. The fact that they’ve got through the game makes it really pleasing.
“As I’ve said, though, the No.1 priority is staying fit. It’s all very well getting a pat on the back for winning a friendly but if you don’t have half the team on the first day of the season there will be questions asked.
“We want to get through these six games and then go from there with everybody fit."
Villa head to the United States this weekend for matches against Houston Dynamo and FC Dallas, and Lambert added: “We’ll meet Guzan over there and Ron will meet us in a few weeks’ time. Philippe will go too. The only one I have given extra time is Ron for his efforts in the World Cup."