Barcelona youth product Nolito came back, in Celta Vigo colours, to haunt the side which developed him.
for former Liverpool flop Iago Aspas, as Barcelona crashed to its first defeat of the La Liga season.
Plenty of players have scored against a former club. Some rub it in, some look close to tears.
The World Game has taken a look at some of the best.
Frank Lampard v Chelsea
Frank Lampard is one of Chelsea's best ever players, scoring an astonishing 211 goals in 13 years at Chelsea, so it was surprise to see him pop up in a lighter shade of blue after Jose Mourinho decided his time at Stamford Bridge was up.
Chelsea visited the Etihad in September last year, and had a 1-0 lead with only minutes to go. But James Milner dropped a ball into the area, and there was Lampard, showing the timing which reaped so many goals down the years, to prod home for Manchester City.
He didn't celebrate, in fact he didn't know how to react, and neither did the Chelsea fans, who gave him a rapturous reception at full time.
"I knew it", John Terry said to him after the game, and deep down, the Chelsea fans did too.
Sebastian Ryall v Melbourne Victory
And then there are those players who pop up and score often against their former clubs, appearing time and time again, like a thorn in the side.
Three of Ryall's nine A-League goals have come against Victory, while he was also in February this year, although he was exonerated by Football Federation Australia.
The pick of the bunch for Ryall was this slaloming run - and boy did he celebrate.
Robin van Persie v Arsenal
Van Persie scored against Arsenal at Old Trafford (with more than a little help from the hapless Thomas Vermaelen), and at the Emirates from the penalty spot, in 2012-13 after his $52 million transfer.
He didn't celebrate.
When United hosted Arsenal in November 2013 though, that all changed. Van Persie's thumping header from a Wayne Rooney corner decided the game between the two table toppers.
Van Persie celebrated wildly, but 12 league goals saw the David Moyes era begin with a damp squib as United finished seventh. Arsenal meanwhile, finished fourth.
Emmanuel Adebayor v Arsenal
This is one of the all time great, rub your nose in it celebrations the game has seen.
In September 2009, Adebayor scored for Manchester City against Arsenal. He didn't just celebrate, he went nuts.
The ball had barely reached the back of the net when Adebayor spun around and ran the length of the Etihad Stadium pitch to celebrate in front of the incensed Arsenal fans, finishing his lung bursting run with a big knee slide in front of the Gunners faithful.
Poor taste? Maybe. Great viewing? Absolutely.
Denis Law v Manchester United
"Denis has done it" said commentator Gerald Sinstadt as Law's goal, in the last game of the 1973-74 First Division season, condemned Manchester United to defeat. United was relegated too, which would have happened by virtue of other results anyway. But don't let that take away from the folklore.
In fact, the match was abandoned in the 85th minute, four minutes after the goal, but the Football League decided the result would stand.
Law didn't celebrate - he was a club legend at United after 11 seasons there which reaped 237 goals in 404 games.
And, after helping (sort of) to relegate United, he's a club legend in the blue half of Manchester too.
