The Gunners battled to a 2-1 win at West Ham on Sunday to leapfrog the home side and move level with Southampton, whom they play at St Mary's Stadium on New Year's Day.
It was a fifth victory from the last six matches in all competitions, as despite all of their defensive shortcomings, Arsene Wenger's men are building some momentum, with only one defeat since the end of November.
Welbeck, who scored Arsenal's second goal just before half-time, insists focus must be completely on the here and now.
"The most important thing for us is to concentrate on the next game because we can't afford to look too far ahead," Welbeck said.
"We have just got to make sure that we're ready for each and every game."
Welbeck, quoted on www.arsenal.com, continued: "The win (at West Ham) puts us back in amongst it and we need to be further up the table.
"We want to be gaining points and put the pressure on the teams around us."
After seeing an early 25-yard effort from former Gunners midfielder Alex Song somewhat controversially ruled out for offside, Arsenal took the lead through a penalty from Santi Cazorla on 41 minutes, with Welbeck sliding in a second at close range just before half-time.
Even though Cheikhou Kouyate reduced the deficit at the start of the second half and West Ham had plenty of pressure, the Gunners should have put the result beyond doubt, but were denied several times by in-form goalkeeper Adrian.
"We missed a couple of chances - I had one and some of the other players had one where we could've maybe won the game earlier
That is something we need to improve on," Welbeck said.
Arsenal have played the Saints twice already this season, losing in the Capital One Cup, before winning the league match at the start of December.
Welbeck said: "Southampton gave us a difficult test at home and we know how well they have been doing this season, so we have to prepare physically, mentally and tactically right for this game.
"Going into the new year, we want to start it off well."
Arsenal will again be without suspended forward Olivier Giroud at Southampton, where Theo Walcott could be set for a long-awaited start having recovered full fitness.
Francis Coquelin, recalled from a loan spell at Charlton, impressed in a defensive midfield role against West Ham, while Tomas Rosicky was given a breather having suffered calf and hamstring cramps after a rare start on Boxing Day, so could be available again.
Wenger, meanwhile, insisted there was "nothing concrete" in reports German forward Lukas Podolski was set to leave for Inter Milan in January.
"At the moment nobody goes out," the Arsenal manager said.
"We have (Mesut) Ozil coming back now at the beginning of January, so of course there is a lot of competition up front."
Source : PA