Spain's Atletico Madrid, Italy's Inter Milan, and six English teams abandoned the breakaway competition after intense criticism.
Atletico Madrid, Real Madrid and Barcelona are all very much in contention with only eight games each left.
Diego Simeone's side got off to an ideal start when Yannick Carrasco dribbled into an empty net in the fifth minute thanks to a lucky bounce but Betis levelled with a thumping volley from Cristian Tello in the 20th.
The Catalans moved to within a point of Atletico Madrid at the top of La Liga.
Chelsea beat Atletico Madrid 2-0 to reach the quarterfinals for the first time since 2014.
Messi celebrated his record-equalling 767th appearance for Barcelona by scoring two goals in a 4-1 La Liga victory over Huesca.
Robert Lewandowski became the Champions League’s third top scorer of all time as holders Bayern Munich put one foot in the quarterfinals with a 4-1 thrashing of Lazio.
The victory took Atletico on to 41 points after 16 games, four clear of second-placed Real Madrid who have played 18.
The win took Barca above Sevilla and into fifth place in the standings on 28 points, 10 behind leaders Atletico Madrid who beat Alaves 2-1 earlier on and who have a game in hand on the Catalans.
A Luis Suarez header gave Atletico Madrid a 1-0 home win over Getafe in coach Diego Simeone's 500th game in charge.