Young defender looking to avenge the Argentine after he helped Atletico Madrid end the Cottagers' European dreams at the final hurdle in 2010 but is wary of the forward's talents.
Aguero produced a sterling display against the youngster as Atletico Madrid beat Fulham in 2010's Europa League final and Smalling is determined to be on the winning side this time.
"He was a real handful playing up front with Forlan, he looked very sharp," Smalling told The Sun. "Even then he looked like he would go for big money, and that's what happened. Since he arrived, he's really produced for City, scored some great goals and some very important ones. We'll have to keep an eye on him but hopefully it will be me celebrating this time, getting revenge against him would be nice. I'm looking forward to trying, but it's not just him, we can't think too much about him when there's players like Silva and Nasri around, too."
Manchester United's draw at Liverpool last week saw City move two points clear at the top of the League and Smalling is determined to put United back above its neighbor on Sunday."We got a good point at Liverpool last weekend but we need to win this one," he continued. "City are playing really well this season and they're top of the table but hopefully they won't be come Sunday afternoon."
While Aguero will be a key man in attack for City, United will be hoping that Wayne Rooney can recapture his form showed in last season's corresponding fixture that included the goal of the season, Rooney's incredible overhead kick.
Smalling also hopes that Rooney can put his three-game international ban behind him and channel any disappointment into good performances for his club.
"We were all shocked but since then he just seems to have carried on as normal — as you saw by his two goals in midweek," he told the paper. "This is the sort of game he'll thrive in. We all remember that wonder goal he scored last year and I'm sure he's got a taste for more against them."