Barcelona welcome Real Madrid to Camp Nou on Sunday afternoon with vital La Liga points up for grabs in an El Clasico with a difference.

For the first time since December 2007, the Spanish rivals - winners of 13 of the last 14 domestic league titles - will lock horns without Cristiano Ronaldo or Lionel Messi on the field.

Barcelona

While Madrid have failed to adapt to life without all-time leading scorer Ronaldo, Barca simply have to make do without their own record talisman for just a couple more weeks.

A fractured arm has ruled Messi out of this opening El Clasico of the season, giving Ernesto Valverde a selection headache of sorts as he attempts to fill a void that, to put it bluntly, cannot be filled.

Not like-for-like, anyway, as Philippe Coutinho, Malcom, Ousmane Dembele and Rafinha - for all their qualities - struggle to take control of games in the same way as the five-time Ballon d'Or winner. Coutinho and Rafinha, surprisingly, got the nod in midweek as Barca saw off Inter Milan 2-0 in the Champions League, starting either side of regular striker Luis Suarez.

Suarez has just two goals to his name from open play since May, though, while Dembele has blown hot and cold since joining in a big-money deal from Borussia Dortmund over a year ago, not helped by various injury setbacks, and summer signing Malcom has just 28 minutes to his name.

Finding the right formula in attack is arguably not even Valverde's biggest conundrum ahead of Sunday's huge clash, however, as his side have conceded 14 goals in their opening 13 matches this term. The loss of Samuel Umtiti to a knee injury has proved as bad as many inside the club feared, leaving Clement Lenglet and Gerard Pique as Valverde's only recognised options in the heart of defence.

Despite all the negativity, however, Barca head into this match on the back of successive wins, having preceded their victory against Inter - a success that effectively sends them through to the last 16 of the Champions League with three games to spare - with a 4-2 triumph against Sevilla.

That much-needed win, coming in the first of three successive home matches for the Spanish champions, helped to kickstart their season as they had failed to win any of their previous four in La Liga before that.

Dropped points at home to Girona and Athletic Bilbao, as well as a draw at Valencia and defeat away to Leganes, allowed others to close the gap in what is shaping up to be an exciting title race. Not since 2004 have Barca had fewer points at this stage of a season and, even if they do sit top of the pile nearly a quarter of the way through, Valverde knows that the pressure is very much on.

Recent form in La Liga: WDLDDW
Recent form (all competitions): LDWDWW

Real Madrid

It says an awful lot about Madrid's current predicament that Tuesday's 2-1 win at home to Viktoria Plzen - currently the Czech Republic's second-best team - was greeted with a huge sigh of relief.

Los Blancos knew heading into that match that anything other than victory would have made a bad situation a whole lot worse, and simply coming out of the Champions League clash unscathed was all that mattered to Julen Lopetegui.

Even so, many wondered whether Lopetegui - in the job for just four months - would survive the axe before Sunday's El Clasico. With Antonio Conte and Mauricio Pochettino reportedly being lined up by Madrid chiefs, this could be a final farewell for the ex-Spain boss.

In the midst of Los Blancos' worst league start since 2001-02, it is easy to forget that they kicked off their maiden campaign of this new Ronaldo-less era in style by winning five and drawing one of their first six games under their new boss.

A 3-0 loss at Sevilla, a fixture the capital club tend to struggle in, can be pinpointed as the time when it all began to unravel for the reigning European champions, though, with three more defeats and a draw to follow in their next four matches prior to the Plzen win earlier this week.

Seventh-placed Madrid failed to score during the first four of those five games without a win, only ending the worst-such run in their history through Marcelo's consolation in the shock 2-1 loss to Levante last weekend.

Madrid, quite simply, have failed to replace the greatest player in their history, instead making a young and unproven player their marquee outfield signing in the summer and giving him just 12 minutes to make an impression.

If Vinicius Junior can be absolved of any blame for his part in this disastrous run of form, a player of Karim Benzema's ilk cannot, with the Frenchman's underwhelming goalscoring return coming into sharp focus during Madrid's month-long wait for a league win.

A trip to their greatest rivals of all may just be what is required for the 2017 title winners to finally click back into gear; anything less and Lopetegui could be on his way out having experienced this great fixture up close as a manager just once.

Recent form in La Liga: DWLDLL
Recent form (all competitions): LDLLLW

Team News

With Messi unlikely to return to action until the middle of November, and the length of Umtiti's layoff still unknown, Valverde needs to plug gaps at both ends of the field.

Suarez showed in midweek that, while his goalscoring figures are down, he still remain a key link man and his place in the starting lineup is assured.

Rafinha took his big chance when selected for the win against Inter by converting a Suarez cross, which may tempt Valverde - who does not fully trust Dembele - to go with the same front three for the visit of Madrid.

Arthur has been hugely impressive in the middle since arriving in the summer, meanwhile, and there is no displacing Sergio Busquets and Ivan Rakitic in what is a settled midfield and defensive setup, assuming Sergi Roberto is used at right-back.

In terms of the visitors, Dani Carvajal is carrying a calf injury and Marcelo - on the scoresheet in Madrid's last two outings - is also not fully fit.

Nacho is therefore on standby, and Alvaro Odriozola is a more-than-capable replacement, but Marcelo will be given every chance to prove his fitness.

Los Blancos recently welcomed Isco back to action and may use the Spanish attacker at Camp Nou this weekend, but Benzema, Gareth Bale and Marco Asensio are the more likely candidates to start.

Barcelona possible starting lineup:
Ter Stegen; Alba, Lenglet, Pique, Roberto; Arthur, Busquets, Rakitic; Coutinho, Suarez, Rafinha

Real Madrid possible starting lineup:
Courtois; Marcelo, Varane, Ramos, Nacho; Kroos, Casemiro, Modric; Asensio, Benzema, Bale

Head To Head

Sunday's game will be the 239th between the two sides, with Madrid winning 95 of those to Barcelona's 93.

This corresponding fixture last season finished 2-2 - Bale hitting a sublime equaliser for the visitors to rescue a point, although Barca survived more than half the match with 10 men after Roberto's red card.

Barca were 3-0 winners at the Bernabeu in last season's other league match, but their recent record in this fixture is pretty mixed as they have won four, lost three and drawn two since the start of 2015.

We say: Barcelona 2-1 Real Madrid

Despite making their worst start to a season in 13 years, Barcelona still find themselves top of La Liga and well on course to reaching the last 16 of the Champions League. Dig a little deeper below the surface and it is clear to see that all is not well at Camp Nou, yet they have more momentum than arch-rivals Madrid, who have lost four of their last six in all competitions and have badly struggled in front of goal. This, then, is not an ideal fixture for under-fire boss Lopetegui to save his job.