Kell Brook provided an emphatic answer to those questioning if he is finished with boxing with a two-round demolition job of Sergey Rabchenko on Saturday.
After considering retirement just three months ago, Brook showed he still has a future in boxing with an impressive debut at super welterweight and a return to winning ways.
Brook (37-2, 26 KOs) could not afford another defeat after being stopped by American Errol Spence and Kazakhstan's Gennady Golovkin in his previous two fights.
The 31-year-old also suffered broken eye sockets in both world title losses to Spence and Golovkin, which left him suffering from depression and seeing a counselor before deciding to resume his career.
After losing his IBF world welterweight title in an 11th-round defeat to Spence in May, Brook got just the confidence boost he needed by flattening Rabchenko (29-3, 22 KOs) with a right hook to the temple in front of his home city fans at the Sheffield Arena, England.
"You thought you got rid of me -- I'm the terminator and I'll be back," Brook said in the ring afterward.
"I'm here to stay. I've put everyone else in the division on notice." It was all about getting timing right, and I was getting it right and I knew I buckled him. Timing beats speed. I felt very comfortably. I've only gone up 10 pounds from yesterday -- I felt strong at the new weight.
"I was in a dark place at Christmas. I needed to get back to winning ways. I'm back at it."
For the first time in nearly two years, Brook did not finish a fight with a grotesquely swollen face and as a loser.
Brook suffered a broken left orbital bone against Spence after fracturing the other eye socket in a fifth-round stoppage defeat to WBC-IBF-WBA world middleweight champion Golovkin in September 2016.
Spence and Golovkin, whom Brook stepped up two weight divisions to challenge, were considerably harder tasks than Rabchenko, from Belarus.
But former European champion Rabchenko had seven previous professional wins on English soil and knew Brook from sparring sessions two years ago.
Brook, who made three IBF title defenses before losing to Spence, was immediately into his stride by landing an array of accurate punches in the first round.
Rabchenko, who was in his third fight since being stopped by Detroit's Tony Harrison in July 2016, was floored and counted out after Brook landed a right hook to the temple in the second round.
Moments earlier, Brook uncorked a sweet left uppercut to rock Rabchenko before finishing him with the right hook.
It was an impressive finish to show Brook's career is far from over.
A fight against British rival Amir Khan is the fight Brook wants -- perhaps later in 2018.
"Everyone wants to see that fight [with Khan]," Brook said. "We've got the same promoter, so why can't it happen?
"We need to talk about weight and make it happen."
Brook and Khan are both promoted by Eddie Hearn, who said: "Amir Khan and Kell Brook is the fight we've wanted for three or four years. Amir Khan has got to pass the test on April 21. Kell will box again in June. Later in 2018, everyone wants Kell Brook against Amir Khan."
Earlier in the night, Gavin McDonnell outworked his younger English rival Gamal Yafai to win a super bantamweight contest 116-112, 116-112, 117-113.
In the first half of the fight, there was little between the two, who are trying to emulate the success of their world champion brothers.
McDonnell (19-1-2, 5 KOs), 31, the twin brother of WBA "regular" bantamweight titleholder Jamie McDonnell, had experience on his side after being out-pointed in a shot at the vacant WBC super bantamweight title by Mexico's Rey Vargas a year ago.
And it was that experience, along with stamina, that proved decisive for McDonnell.
McDonnell, No. 6 with the WBC, dominated the second half of the fight and spent most of the time on the front foot behind his longer jab.
Yafai (14-1, 7 KOs), whose elder sibling Kal is WBA world super flyweight champion, is five years younger, but it was McDonnell who was fresher from the 10th round.
In the last minute of the 10th, Yafai was in trouble and weary as he was caught by McDonnell's accurate attacks.
"You can't jump levels in boxing, and I've ticked all the boxes coming up," said McDonnell.
"Credit to Gamal, he jumped up from British level to world level. It was what I needed, my career was on line. I had size, reach, weight and experience. I don't know how the bookmakers made him favorite. I know a lot of my mates have lumped on me, so I want 10 percent."
English heavyweight David Allen suffered a long cut along his right eyebrow after an accidental clash of heads in the first round against Jamaica's Lenroy Thomas.
The cut was so bad the fight was stopped and Commonwealth champion Thomas retained his title via a technical draw.
Allen lost the Commonwealth belt to Jamaica-born Thomas on a split-points decision on the undercard of Brook-Spence.
Florida-based Thomas, 32, has revived his career after a third-round knockout defeat to Russia's Andrey Fedosov in ESPN's 2015 Boxcino Tournament, but this was a frustrating night for him as well as Allen.
"Disappointing after all the work I put in, sparring Deontay Wilder, we have to do it again," said Thomas.
Featherweight Kid Galahad, Brook's stablemate at the Wincobank Gym in Sheffield, marked his birthday with a stunning third-round finish.
Galahad (24-0, 15 KOs), 28, uncorked a perfectly executed left cross to knock out Irving Berry (23-8-2, 10 KOs) of Panama in the third round.
Galahad, whose real name is Abdul Barry Awad, is hoping to land a world title fight this year against either Lee Selby or Josh Warrington. The British rivals clash for Selby's IBF world featherweight title in Leeds on May 21. Galahad is the IBF No. 5, with just Joseph Diaz Jr. and Carl Frampton ahead of him in the rankings other than champion Selby and Warrington.
"Kids don't want to fight me because I'm unorthodox," Galahad said.
"I want the winner out of Warrington and Selby, that's the one I want."
Galahad's career was interrupted by a ban in 2015 for a failed drug test -- but he claimed his brother put the banned substance in a protein shake after a row.
Since returning from the ban, which saw him out of the ring for 19 months, Galahad has stopped six consecutive opponents and looks worthy of a title shot soon.