Lionel Messi came on as a substitute in the second half to help Barcelona secure a lead, but they weren't able to hold it as a late tally from Ander Herrera earned a 2-2 draw for Athletic Bilbao.
After an opening quarter hour which saw both clubs playing with a sense of caution, Barcelona created the first notable scoring chance of the match courtesy of Alexis Sanchez. The 24-year-old forward dribbled his way into prime position and cracked a nice shot that was unlucky to find the post.
The chance seemed to spark Barca. They finally started to establish their usual possession dominance and were able to spend a lot of time in the attacking third. Xavi found space and looked ready to give his side the lead, but his shot narrowly missed wide.
Just as it appeared the La Liga leaders were going to take complete control, Athletic struck on a counterattack. Aritz Aduriz broke to the outside and played a laser cross through the six-yard box, where Markel Susaeta easily touched it into the net for a 1-0 lead.
Aduriz almost made it a two-goal advantage shortly before halftime. Oscar de Marcos delivered a perfect floating cross into the box for a header from Aduriz, who sent it over the top. The strong finish from Athletic made Barca fortunate to escape down by just one.
It was a situation that perhaps shouldn't have been a total surprise, based on a stat Infostrada Sports passed along:
The sluggish play continued from Barcelona after the break. They weren't able to execute the short, quick passes that usually make them so tough to defend. While Athletic certainly deserve some credit for solid defending, the league's top squad simply wasn't playing up to their usual standards.
Tito Vilanova decided to bring Messi off the bench to provide a spark with about 30 minutes to go. To say it worked would probably be an understatement. Suddenly, Barca was dangerous again.
In the 67th minute, Messi showed why he's won four straight Ballon d'Or awards with an amazing individual run. He found himself trapped between three defenders, and in the blink of an eye, he was able to break free and easily slotted it past Gorka Iraizoz.
Two minutes later, Messi worked his magic again. He set up a chance for Alexis, who was able to remain onside, quickly turn toward goal and give Barca the lead.
It wasn't enough to secure the victory, though. Athletic was able to keep them at bay after that strike and was able to score a late equalizer. Ander Herrera picked up a loose ball in the box and just managed to sneak it by Victor Valdes.
There are two ways to look at the result for Barcelona. On one hand, they could have walked away with no points if not for the heroics of Messi. Yet, they still let two points slip away in the final moments, which won't please Vilanova.
They will need a more complete showing on Wednesday to have any chance at a miracle comeback against Bayern Munich.
Key Player Grades
Gorka Iraizoz (Athletic Bilbao): C+
Iraizoz didn't face as much pressure as he probably expected heading into a match against Barcelona, but there was nothing he could have done to stop the first goal. When a player like Messi is able to break free, he's almost impossible to stop.
Although he wasn't the only player to blame on the winner for Alexis, he should have done better. He was able to get a slight touch, but it wasn't enough to keep it out. Iraizoz produced a couple of nice saves along the way, but overall, it was an average showing en route to a point.
Aritz Aduriz (Athletic Bilbao): B+
It was a terrific all-around showing for Athletic's leading goal scorer. He generated multiple chances in the first half, both for himself and teammates, and it paid off with an assist on the first goal. Aduriz should have done better on a header attempt that could have stretched the lead.
He wasn't able to make as large of an impact in the second half as Barcelona began to control possession, which caused him to come out 15 minutes from time. He still did enough throughout the match to earn a high grade for his effort.
Alexis Sanchez (Barcelona): A-
Sanchez certainly made his presence felt throughout the match. He was making frequent runs and putting pressure on the Athletic back line. The talented forward was unlucky to hit the post in first half, but finally had the ball bounce right for him to score in the second.
He receives high marks mostly because he was one of the few players making plays before Messi's arrival. While the rest of the attacking group struggled to find their footing, he excelled. It paid off for him with a well-deserved goal before subbing out late.
Gerard Pique (Barcelona): C
Aduriz beat Pique clean on the first goal. If he would have played it better, the striker wouldn't have been able to complete the pass to Susaeta. It was a rare lapse from the Spanish center-back, and his club paid the price for it.
That said, the back line did perform much better in the second half, especially early before Messi arrived to save the day. Still, it was far from his best performance and that's going to stand out in a match where Barca didn't earn all three points.
Athletic Bilbao returns to the pitch next Friday against Celta Vigo. The Lions will be looking to build off the momentum generated late in Saturday's match to finish the season strong.
Barcelona must start preparing for the second leg of their Champions League matchup with Bayern Munich on Wednesday. Barca needs to overcome a massive four-goal deficit at home.