England striker Rickie Lambert opened the scoring after 20 minutes before Rodriguez struck two minutes before half-time as the Saints moved up the table to sit behind only Arsenal and Liverpool.
While they may be overtaken on Sunday, Rodriguez was taken aback to discover their position following the game but was adamant they can go further.
He told Sky Sports 1: "That is unbelievable.
"We have got the belief, we just need to push on. I'm well chuffed.
"There is no limit to what we can we achieve.
"We just need to keep the belief."
Rodriguez emphasised the team's hard work and spirit as reasons behind their success which has taken many by surprise.
He said: "I don't think it is a secret really.
"We are a hard-pressing team, we work hard and we are honest.
"Great players, great talent, a great team to be in.
"We are focused on what we are working on, he (manager Mauricio Pochettino) has got us working with belief.
"I am just looking forward to to the next game, I don't think we are going to change anything to be honest.
"Training is extremely hard; the lads have really taken to it and it is showing on the pitch."
He also pointed to working alongside the likes of fellow Englishman Lambert, saying: "I have learned so much from him, he is great to play with."