Premier League - Villa share spoils at Everton
The game was marked out, though, by an extraordinary 26-second spell midway through the second half.
First, Jermaine Beckford's shot appeared on replays to have crossed the line but the goal was not awarded.
Then, as Everton raged at the decision, Bent surged up the other end and struck his second to put Villa ahead.
A soft penalty for the hosts after Jean Makoun's foul on Phil Jagielka - the first spot-kick Everton have been awarded in the Premier League all season - was then dispatched low down the middle by Baines to seal a draw.
On a sunny afternoon on Merseyside and a pristine surface, the players produced an entertaining and end-to-end first 45 minutes.
Both sides had their chances - with Villa's Stewart Downing sounding the first warning with a solo run down the right. Cutting back inside and skipping through tackles, it took a lunging block from Sylvain Distin to deny him a stunning opener.
Everton responded, going close when the ball bounced the way of an unmarked Beckford, and Brad Friedel was forced into an impressive full-stretch stop.
Moments later Baines and Osman combined, with the latter trying a shot from close range which Friedel smothered.
As the half unfolded, the biggest surprise was that there had been no opener.
Villa again came close, with Reo-Coker's lashed effort requiring another despairing block from Tony Hibbert after half an hour.
Both sides threatened, but it was the home side who broke the deadlock, with Diniyar Bilyaletdinov holding the ball up expertly before playing a weighted pass into Osman's path. Osman continued his run, turned away from James Collins before firing a low shot at goal which squirmed under Friedel.
The visitors, fighting a relegation battle, looked short of ideas, but a freak injury to Beckford just before the break caused concern for the hosts.
In the end the striker hobbled his way to the half-time whistle and was able to continue in the second period.
And the Toffees had bigger problems when a more-determined Villa struck an early equaliser.
Downing was the architect, sauntering down the right wing before playing a simple pass across for England team-mate Bent, who tucked the ball away confidently at the near post.
Everton fought their way back into the game, going close with a Johnny Heitinga header just before the hour and Osman remaining a threat.
The hosts looked to have got themselves back in front when Beckford's pacy shot thundered against the underside of the crossbar and looked to have crossed the line - but to their amazement the goal was not awarded.
And still struggling to understand the decision, they were caught napping as Bent surged forward and tucked a classy finish past Tim Howard for his fifth Villa goal since his £18m move.
The chances continued to flow, however, and Everton should have equalised with a quarter of an hour remaining.
A well-worked set piece saw Baines play in Bilyaletdinov on the left, before his delivery popped up in front of Osman, who could not keep underneath it and spooned the ball over the crossbar.
Everton continued to press, and though Makoun made minimal contact to give away the penalty the hosts deserved the draw which Baines's spot-kick handed them.
That said, a point did little for Everton's slim hopes of reaching Europe or Aston Villa's battle to avoid relegation.