Coming off Wednesday’s 6-1 trouncing of Celtic in the final group match of Champions League play, it appears Barcelona have regained their footing after disappointing letdowns to Ajax and Athletic Bilbao.

The Spanish giants made it to the UCL’s Round of 16 and remain two goals ahead of Atletico Madrid atop the La Liga table, but will need to find reinforcements next month to keep their multi-championship aspirations alive.

Boss Gerardo Martino is employing the strictness caution when it comes to midfielder Andres Iniesta, who sat out the Copa del Rey victory over Cartagena and the Celtic drubbing. Going forward Martino and Camp Nou officials might explore options to keep Iniesta fresh for the season’s final push.

The first option involves Borussia Dortmund midfielder Ilkay Gundogan, a highly touted and sought after 23-year-old German. According to Daily Mail, Manchester United are reportedly worried by the Catalans' interest, which could start a bidding war for Gundogan’s services.

Real Madrid and Arsenal are also in hot pursuit of Gundogan, but Barcelona may have taken the inside track with officials reportedly sitting down with his father. Netting six goals in 57 appearances for the Bundesliga club, Gundogan will certainly ask for a hefty increase of his £25,000-a-week wage, but Dortmund could also ask for a considerable fee with the player under contract until the end of the 2015.

Barcelona could also upstream United for available Inter Milan midfielder Fredy Guarin, as reported by The Express last week. Martino may even favor Guarin over Gundogan, as he specifically asked club president Sandro Rosell to bring on the 27-year-old Colombian. Guarin’s previous work under current Tottenham manager Andre Villas-Boas at Porto, along with Chelsea and United’s interest could however complicate a switch.

In other news, the Catalans may try to fortify their backline with Chelsea defender David Luiz for a fee as high as £29 million, according to Daily Star. Injury concerns surrounding Carlos Puyol and Gerard Pique have left Barcelona and Martino seeking more depth on defense, and the Brazilian center back has seen his playing time shrink due to a knee injury and new lineups instituted by Jose Mourinho’s return to Stamford Bridge. Luiz was even linked to Barcelona in the summer.

Second in command of Brazil’s national team with 33 career caps, Luiz could certainly use more pitch time ahead of the World Cup, something Barcelona could provide even at such a high monetary cost. Luiz has made 67 appearances in two years with Chelsea, netting six goals after an extended four-year stay with Benefica.

Looking beyond the January session, Barcelona continues their search for a new star keeper should Victor Valdes stay true to his word and move on next summer. The latest rumor pegs Real Sociedad’s Claudio Bravo as a top target, according to Talk Sport.

Bravo has recorded five clean sheets and 48 saves, while allowing 21 goals in 15 matches this season. Manchester City are also intrigued by the Chilean’s skills in net, and he could be an excellent bargain at a £3.5 million market value. However, his exorbitant buy out clause could put a damper on any more transfer talk.