Unbeaten in the last four and with three wins on the bounce, the Hammers have flown up the table and now sit in 11th spot in the Premier League.
Despite having put some daylight between themselves and the other relegation-threatened sides, Allardyce is keen for his players to keep fighting and not to get complacent.
"Our problem early in the season was scoring goals to win the points. Now everyone is fit we're putting both together.
"There's more competition for places. Winston Reid can't get in at the moment because the players who are starting are doing a fantastic job."
He added: "We have to maintain our good form when we play Southampton. There's a long way to go to get safe so we have to keep it up."