Adam Hammill's stoppage-time equaliser rescued a point for Barnsley as they came back to earn a 2-2 draw with Bristol City after surrendering a first-half lead.Marley Watkins had put the hosts in front before City went in front with goals from Lee Tomlin and Tammy Abraham. Barnsley's Sam Winnall also missed a penalty.Barnsley posed an early threat when Ryan Kent's ball across the face of goal just evaded Winnall, who was running in at the far post.City's Aaron Wilbraham then had a shot deflected wide and Adam Armstrong was forced to make a vital challenge when Abraham broke into the right-hand side of the area.The breakthrough came midway through the half when Andy Yiadom's floated cross was met by a close-range header from Watkins (21).Kent's low shot from inside the area was saved by Frank Fielding and the keeper was also equal to Armstrong's effort.As the visitors looked for a response, Tomlin put a free-kick narrowly wide.Barnsley continued to enjoy the lion's share of possession, however, with Josh Kay's long-range effort going over before they were awarded a penalty at the end of the first half.In the third minute of time added on, Winnall was fouled by Scott Golbourne and referee Geoff Eltringham immediately pointed to the spot. Winnall stepped up to take the penalty, which was saved by Fielding with an outstretched leg.There was a promising opening for the hosts in the opening stages of the second half when the ball fell kindly to the unmarked Angus MacDonald at the far post following Kent's cross, but the defender's firm drive lacked direction.The equaliser came from the penalty spot in the 58th minute when Tomlin hammered his spot-kick into the centre of the net after Adam Jackson's handball.The home side then enjoyed a decent spell with Armstrong striking the bar from 25 yards out and Watkins having an angled shot saved.Fielding also did well to keep out a shot from Yiadom while Kent had an effort deflected wide.The visitors went close to scoring when Wilbraham's header forced a superb save from Adam Davies, who turned the ball onto a post, with the loose ball cleared by Yiadom.City took the lead in the 76th minute when Tomlin broke free inside the area and laid the ball off to Abraham who finished with ease.Winnall put a header on target from a James Bree cross, which was comfortably saved.With time running out, Barnsley needed a flash of individual creativity and it came in stoppage time when substitute Hammill cut in from the left and found the far of the net with a perfectly executed shot.There was still time for the visitors to threaten a winner with Tomlin trying a long-range shot which was saved by Davies.