MOSCOW -- Three quick thoughts from Brazil's 2-0 win over Serbia, which sees the Selecao move on to the round of 16 as Group E winners.

1. Brazil into knockout rounds looking like frontrunners

Brazil avoided joining Germany in this summer's list of big-name casualties, showing signs during a 2-0 win over Serbia that they should be considered frontrunners to win what would be their sixth World Cup. Paulinho and Thiago Silva each scored in a watchable game that, despite one or two scares, Tite's side eventually won in comfort. They top Group E and will now face Mexico in Samara on Monday.

A lively Brazil start was derailed slightly when Marcelo, who had been struggling after taking an early knock, signalled that he could not continue and was replaced by Filipe Luis in the 10th minute. The left-back hobbled down the tunnel in visible pain, although he was later revealed to have suffered a back spasm that should not be a long-term concern.

His team continued to fizz the ball around promisingly in the final third and created their first real chance when Neymar, profiting from tenacious play from Gabriel Jesus, forced Vladimir Stojkovic to tip away a cross-shot. A far better opportunity arose when Neymar, from virtually the left-back position, sent Jesus away. He only had Stojkovic to beat, but opted to check onto his right foot, by which time Nikola Milenkovic had recovered to block his effort.

By now Brazil were playing some excellent football and, when Paulinho struck, the goal was deserved. He made a lung-busting run beyond a dozing Aleksandar Kolarov to reach Philippe Coutinho's lofted pass from the left and knock the ball past the advancing Stojkovic; it was a fine piece of initiative from both players, and now Serbia needed to score twice.

For a team of Brazil's counterattacking quality, that kind of situation is heaven sent. Neymar could have proved the point 10 minutes after half-time after another beautiful Coutinho pass, but took too much time and allowed Stojkovic to save.

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That briefly sparked Serbia into life, and Aleksandar Mitrovic, reacting to Alisson's error from a right-wing cross, headed at Thiago Silva with most of the goal gaping. Mitrovic then saw a towering header saved and, such is the way football works, he was punished for both misses.

Thiago Silva inflicted the killer blow, thudding home a near-post header from Neymar's corner as bodies grappled around him in the box. He had been the only player with his eye on the ball; Brazil's own focus had been similarly keen for most of the game, and they showed no sign of letting it slip after that.

2. Coutinho the conductor as Brazil's attack clicks

At last Brazil started to find all the angles, combinations and quick-fire exchanges that characterise their best work -- and the man at the heart of it all here was Coutinho, who is blossoming into one of this World Cup's stars.

It was Coutinho who finally illuminated a troubling team performance against Costa Rica on Friday, breaking the deadlock late on, and here he was on similarly menacing form from the start. He revelled in the pockets created for him in the No. 10 position by the movement of Neymar, Jesus and Willian, and took full advantage; the result being that Brazil looked a more exciting attacking unit than at any previous point in Russia 2018.

The vision Coutinho showed in cutting sharply inside to weight his 40-yard assist for Paulinho was sublime. The execution of that second-half pass from which Neymar should have doubled their lead was similarly sharp. Against a dogged and physical Serbia side, he brought exactly the vision Brazil needed to avoid frustration.

Those around him were in sync too. Neymar will have been disappointed not to score, and saw two more efforts blocked by Stojkovic late on, but put in his most selfless performance for some time -- if we ignore the exaggerated rolls he made after one late challenge from Adem Ljajic -- and combined well with Jesus at times. Willian provided balance on the right and Brazil looked a team on the same wavelength throughout.

Despite a few nervy moments, Brazil ran out 2-0 winners over Serbia with little trouble. Stuart Franklin/FIFA via Getty Images

Perhaps it was the knowledge that the tournament really is opening up for them, or perhaps it was a natural consequence of cranking up the tempo as the stakes get higher. Either way, this was much more impressive fare than Brazil had provided in their first two games and, while there is certainly room for more prolonged periods of quality, at times their front players looked close to their beguiling best.

A Mexico defence that conceded three times to Sweden earlier in the day could provide obliging opposition in the round of 16.

3. Kolarov goes from hero to villain

Kolarov was the hero in Serbia's first Group E game, but this time it was his moment of inattention that took a relatively tight game away from his team -- not to mention their grasp on a place in the knockout stage. The Roma left-back is outstanding over a dead ball, as he showed in scoring the free kick that downed Costa Rica, but he has long been more suspect defensively, and that was sorely evident when he switched off to allow Paulinho his run on goal. No defender should let an opponent run off him like that at this level and it meant a clearly capable Serbia side had a mountain to climb.

In comparison to Brazil, the Serbian lineup looked like the land of the giants. Only two of their starting XI were under 6 feet tall and, at 5-foot-11 and 5-foot-10, respectively, Dusan Tadic and Antonio Rukavina were hardly at a height disadvantage themselves. They are a physically imposing outfit with plenty of technical ability, but eventually neither aspect was enough.

During the first half, they were unable to operate at the same speed and tempo as Brazil. In the second, they enjoyed a couple of intense spells of pressure, Ljajic and Sergej Milinkovic-Savic upping the ante and forcing their opponents back. If Mitrovic had put one of those headers away -- the first was a sitter -- at 1-0, then the latter stages would have been interesting, but ultimately inattention at both ends cost them dear.

They will go home early and the nagging sense, once again, is that they could be better than this.