United held on at the Etihad Stadium, having just one shot on target and 31 per cent possession, with City spurning several chances to strike a blow to their neighbours' hopes of finishing in the Premier League's top four.
Guardiola selected Pablo Zabaleta and Aleksandar Kolarov, 32 and 31 years old respectively, at full-back, with Bacary Sagna, 34, and Gael Clichy, 31, unused on the bench.
The Catalan coach has deployed the likes of Dani Alves, David Alaba and Philipp Lahm as key attacking players from full-back in the past, with Jesus Navas' recent conversion from winger to defender hinting at Guardiola's exasperation with his options in that area of the pitch.
But that was laid clear after Thursday's stalemate.
"I don't like too much to go to the forwards today in attack, I like to attack in other ways," Guardiola told Sky Sports.
"They are waiting for your mistake to punish you. They can play and have a lot quality but they defend so compact and wait to punish you behind your full-back, and we don't have full-backs to go up and down, up and down, because all of them are 33, 34 years old, so I adapt with the quality of players.
"Last games we played with Jesus and we attack a lot with the full-back, but Pablo, Sagna, Kolarov and Clichy - all of them they are more than 33 years old and they don't have the legs to go up and down. That's why I prefer they play in other positions."
Gabriel Jesus made his return from a broken metatarsal as a second-half substitute and looked to have continued a glittering start to his City career with a stoppage-time goal, but he was adjudged offside from Sergio Aguero's cross.
Nevertheless, the 19-year-old's impact off the bench left Guardiola wondering what might have been had he arrived at the start of the season and not been sidelined by injury.
"Always I will think what would have happened if Gabriel Jesus would have been with us all the season," said Guardiola.
"We didn't buy another striker because he could not come before January, so we missed four or five months without him. His impact was amazing. I'm pretty sure with these kind of chances that we had things would be a little bit different, but it is what it is."