LIVERPOOL: Xabi Alonso said his return to Anfield was bittersweet after Liverpool thrashed Bayer Leverkusen 4-0 on Tuesday, thanks to a Luis Diaz hat-trick, to go top of the Champions League table.
Cody Gakpo was also on target as the Reds maintained their 100 percent record in Europe after four games.
Alonso, a Champions League winner during his playing days in the Liverpool midfield, turned his back on succeeding Jurgen Klopp to remain at Leverkusen after leading them to an unbeaten German league and cup double last season.
The Spaniard's name was chanted by the home support in the closing stages.
Liverpool, though, are not left wondering what might have been as Arne Slot continued his stunning start as manager with a 14th win in 16 games in all competitions.
"One thing is the game and the other thing was the reception," said Alonso, who played for the Reds between 2004 and 2009.
"I have a bitter feeling but I really appreciate and (I'm) thankful that after so many years I come here and still have that bond with the club. But it would have been nicer with a better result."
Leverkusen remain on seven points from their opening four Champions League matches after another sobering night for their ambitions to match the heights they hit last season.
Alonso's men sit fourth in the Bundesliga, seven points adrift of leaders Bayern Munich, and failed to master what their coach described pre-match as a "beautiful challenge".
Slot's decision to move Diaz into a central role up front proved inspired as the Colombian struck his first hat-trick for the club.
Sleepless night
Just like in Saturday's 2-1 win over Brighton that took Slot's men to the top of the Premier League, it took until the second half for both Liverpool and the Anfield crowd to come to life.
"Second half we could adjust the gameplan, we took more risks and we were better with the ball as well," said Slot.
"If you work or play at Liverpool you always feels pressure but we embrace this because we want to complete for everything. You have to accept if you work or play here you can enjoy these incredible evenings."
A cagey tactical battle was sparked into life on the hour mark by a moment of stunning quality.
Curtis Jones spun his marker before splitting the Leverkusen defence with a pinpoint pass for Diaz, who nonchalantly chipped the advancing Lukas Hradecky.
Two minutes later, Liverpool killed the visitors off with another flowing move.
Mohamed Salah's driven cross was headed in at the back post by the flying Gakpo.
The linesman raised his flag to momentarily silence the celebrations, but a VAR review showed the Dutch forward was onside for his sixth goal of the season.
Victor Boniface headed wide with a huge chance to bring Leverkusen immediately back into the game.
Instead, Liverpool pulled further clear seven minutes from time when Diaz controlled Salah's looping cross and fired home.
The Colombian then rounded off the scoring with his ninth goal of the season in stoppage time with another clinical finish after Darwin Nunez's blocked shot fell into his path.
Liverpool's return of 12 points means they are almost certainly already assured of a place in the knockout phase, but are closing in on sealing direct progression to the last 16 via a top-eight finish in the 36-team league.
Leverkusen slip to 11th but Alonso is confident of progressing with three of their remaining four games to come at home.
"We are in a good position to fight to go through to the next round," he added. "Today it will be tougher to sleep but we have time to see the positives as well."