Arsene Wenger has warned his Arsenal stars not to underestimate Southampton as the Premier League's surprise package try to claim another scalp on Saturday.
Wenger's team return to action after the international break with a two-point lead over second placed Liverpool at the top of the table, but third placed Saints can draw level with Arsenal if they win at the Emirates Stadium.
While Arsenal will be favourites this weekend, Mauricio Pochettino's side have already won at Liverpool and drawn at Manchester United this season and the Argentine insists his side, beaten just once in 11 league games, have no reason to fear the Gunners.
"We believe that we can play a very good game and we can get a very positive result in this game -- we always believe that," Pochettino said.
With the likes of Adam Lallana, Rickie Lambert and Jay Rodriguez all receiving England call-ups this seasons on the back of their impressive club form, Wenger is well aware that his side, beaten by champions United in their last league game, will have their hands full to see off the defensively solid Southampton side.
"If they can keep the defensive record they have then they can be very ambitious," Wenger said when asked if Southampton were genuine contenders for a top-four finish.
"All the teams want to press and to win the ball back quickly - there's nothing special in there, but Southampton do it well and that is why they are efficient defensively."
Meanwhile, Liverpool captain Steven Gerrard heads into the Merseyside derby against Everton admitting there will be a "huge hole" in his career if he retires without winning the Premier League.
Gerrard has enjoyed a magnificent career with Liverpool and is already regarded as one of the club's all-time greats after almost single-handedly inspiring their 2005 Champions League final win over AC Milan.
The England midfielder cherishes the memory of his heroics that epic night in Istanbul and also a year later in the FA Cup final victory against West Ham.
But he knows the absence of a Premier League winners medal from his glittering CV is a major blemish.
After a strong start to the season lifted Liverpool to second place, Gerrard finds himself in with a chance of finally mounting a serious title challenge
And, speaking before Saturday's clash with hated city rivals Everton at Goodison Park, Gerrard made it clear he won't give up fighting for the crown.
"There'd be a hole missing in my career (without a title win) but I don't think I'd spend the rest of my life being irritated or annoyed or frustrated," Gerrard told ESPNFC.
"Since I broke into this team at 18 years of age I've tried to win the title but it hasn't happened.
"I've got a couple more chances and I'll continue to fight for it."
The 221st Merseyside derby will be Everton manager Roberto Martinez's first taste of one of English football's most frenetic fixtures and he knows the key to taking the bragging rights is stopping Liverpool strikers Luis Suarez and Daniel Sturridge.
"They have had a very good start to the season and are very influential," he said.
Chelsea, four points behind Arsenal in fourth place, can't afford another slip when they make the short trip across London to face West Ham at Upton Park.
Jose Mourinho's men have failed to win their last two league matches, losing to Newcastle and drawing with West Bromwich Albion.
On Sunday, champions Manchester United face Cardiff in south Wales for the first time since 1974.
United went into the international break boosted by a 1-0 win over Arsenal which revived their flagging title defence, but they still have little margin for error in the race to catch the leaders.
Manchester City take on Tottenham in one of the weekend's most eye-catching fixtures between a pair of title contenders both struggling to live up to that billing.
City slumped to a shock defeat at Sunderland in their last match and are six points adrift of Arsenal, while Tottenham are only one point and one place better off after a 1-0 home loss against Newcastle.
Saturday (1500GMT unless stated)
Arsenal v Southampton, Everton v Liverpool (1245GMT), Fulham v Swansea, Hull v Crystal Palace, Newcastle v Norwich, Stoke v Sunderland, West Ham v Chelsea
Cardiff v Manchester United (1600GMT), Manchester City v Tottenham (1330GMT)
West Brom v Aston Villa (2000GMT)