Mauricio Pochettino has warned Tottenham they need a better squad to compete in both the Premier League and the Champions League.

Unless Arsenal beat Aston Villa by an improbable margin, a draw at Newcastle on Sunday will be enough to ensure Tottenham finish second in the Premier League. They are guaranteed a place in the group stages of Europe’s main club competition next term.

Pochettino committed his future to Spurs this week by signing a new five-year deal to stay at White Hart Lane until 2021. But to repeat what they have done this term, Pochettino believes he needs better players.

“We have to improve our squad – this is very clear,” said Pochettino. “We are all agreed about that. The Champions League is a different level, and to compete in that, the Premier League and the domestic cups is very important.

“You need a very good balance. Our challenge is to continue as we have done and the Champions League demands a lot of energy, more than the Europa League. It’s a very different competition.

Tottenham vs Southampton: Player Ratings 12 show all Tottenham vs Southampton: Player Ratings 1/12 Player Ratings? Who impressed at the Lane? 2/12 Hugo Lloris: 5 The Frenchman had little to do throughout the game but was at fault for Steven Davis' equaliser on the half-hour mark and will be disappointed with himself. 3/12 Kyle Walker: 5 Although Dusan Tadic proved to be a little workshy in regards to tracking back Walker rarely got the better of the Serbian midfielder, who was a constant threat. 4/12 Toby Alderweireld: 6 Caught out by Shane Long's pace on a couple of occasions and did not cut the composed figure which has earned him so many plaudits this season. 5/12 Jan Vertonghen: 6 Stepped out from defence confidently whenever the opportunity arose but, like Alderweireld, struggled to cope with Shane Long's speed. 6/12 Danny Rose: 6 The full back was charged with stifling an in-form Sadio Mane and won his individual duel. Far from flawless, but refused to give up on a number of lost causes and bombed up and down the flank in searing heat. 7/12 Eric Dier: 6 The midfielder did not look as assured without Mousa Dembele alongside him and was bypassed by Davis far too easily for the Northern Irishman's second goal. 8/12 Ryan Mason: 5 Started well enough but when Southampton began to turn the screw the game passed the midfielder by. Simply unable to fill Dele Alli's shoes. Julian Finney/Getty Images 9/12 Erik Lamela: 6 Involved in plenty of nice interchanges and claimed an assist for the goal, even if his pass did not appear to be intentionally aimed at Heung-min Son. 10/12 Christian Eriksen: 6 Missed an early chance, which ended up epitomising his entire performance. Encouraging in glimpses but, overall, lacking a cutting edge. 11/12 Heung-min Son: 7 Tottenham's best players. The South Korean scored his fourth goal of the season with an accomplished finish when he refused to give up on what was a lost cause and got his just rewards. A real livewire but eventually ran out of steam and was withdrawn. 12/12 Harry Kane: 6 Not the striker's best afternoon. He did not fashion many chances and spurned the ones which fell his way, the most notable of which was an effort on the stroke of half time when it appeared easier to pass to Erik Lamela rather than go it alone. 1/12 Player Ratings? Who impressed at the Lane? 2/12 Hugo Lloris: 5 The Frenchman had little to do throughout the game but was at fault for Steven Davis' equaliser on the half-hour mark and will be disappointed with himself. 3/12 Kyle Walker: 5 Although Dusan Tadic proved to be a little workshy in regards to tracking back Walker rarely got the better of the Serbian midfielder, who was a constant threat. 4/12 Toby Alderweireld: 6 Caught out by Shane Long's pace on a couple of occasions and did not cut the composed figure which has earned him so many plaudits this season. 5/12 Jan Vertonghen: 6 Stepped out from defence confidently whenever the opportunity arose but, like Alderweireld, struggled to cope with Shane Long's speed. 6/12 Danny Rose: 6 The full back was charged with stifling an in-form Sadio Mane and won his individual duel. Far from flawless, but refused to give up on a number of lost causes and bombed up and down the flank in searing heat. 7/12 Eric Dier: 6 The midfielder did not look as assured without Mousa Dembele alongside him and was bypassed by Davis far too easily for the Northern Irishman's second goal. 8/12 Ryan Mason: 5 Started well enough but when Southampton began to turn the screw the game passed the midfielder by. Simply unable to fill Dele Alli's shoes. Julian Finney/Getty Images 9/12 Erik Lamela: 6 Involved in plenty of nice interchanges and claimed an assist for the goal, even if his pass did not appear to be intentionally aimed at Heung-min Son. 10/12 Christian Eriksen: 6 Missed an early chance, which ended up epitomising his entire performance. Encouraging in glimpses but, overall, lacking a cutting edge. 11/12 Heung-min Son: 7 Tottenham's best players. The South Korean scored his fourth goal of the season with an accomplished finish when he refused to give up on what was a lost cause and got his just rewards. A real livewire but eventually ran out of steam and was withdrawn. 12/12 Harry Kane: 6 Not the striker's best afternoon. He did not fashion many chances and spurned the ones which fell his way, the most notable of which was an effort on the stroke of half time when it appeared easier to pass to Erik Lamela rather than go it alone.

“For that we need to ensure we have a strong squad who can compete in all competitions.”

Tottenham are making progress off the pitch, too, as they aim to move into a new stadium in the summer of 2018.

The project will cost at least £400million but Pochettino insists it will not damage the team’s performance. He added: “We have shown we are ambitious. There are different ways to show it, different ways you can take for success.

“In the last two seasons we have shown our ambition and it’s not only about money. To build a new ground you need money, but to create a good team and fight for trophies is not only about having money.”

On his new deal, Pochettino said: “It’s very important for me. I feel the trust from the chairman Daniel Levy, as well as the players and supporters. I have a fantastic feeling for the future.

“It is important for me to be here for us to continue to develop our philosophy. Our project and our potential is massive and it is exciting to be here.”