It looked like Gylfi Sigurdsson’s goal would continue Swansea’s revival under Francesco Guidolin with a third straight win and see the Welsh side go above West Brom.
But Lukasz Fabianski, who had been in decent form on the night, was finally beaten in the second minute of time added on when Rondon blasted the ball home from close range after a scramble inside the six-yard box, and it finished 1-1.
It was harsh on Fabianski, who had produced good saves to deny Darren Fletcher and Stephane Sessegnon.
West Brom turned down bids for Saido Berahino on Monday and boss Tony Pulis will be hoping his striker will be fit enough to start soon. Berahino, the subject of a £20m-plus bid from Newcastle on transfer deadline day, began on the bench because of a dead leg. He must have wished he was on the field as he watched Fletcher squander three decent opportunities.
After half an hour Swansea’s Sigurdsson saw his dipping volley saved by a scrambling Ben Foster.
Alberto Paloschi came on for his Swansea debut and the £8million signing from Chievo almost made an immediate impact. Paloschi latched on to Wayne Routledge’s through ball but Foster was quick off his line to block the Italian’s shot.
Fabianski finished the half as he began it, acrobatically tipping an effort over the crossbar – this time keeping out Sessegnon’s free-kick.
On 64 minutes the hosts were behind. Leon Britton’s pass broke to Sigurdsson down the right side of the penalty box and he steered a shot across Foster into the bottom corner.
Pulis responded by putting on Victor Anichebe and he saw a well-struck shot brush Fabianski’s fingertips as the ball flew narrowly past the top corner.
Paloschi poked the ball against a post in the 88th minute before Rondon had the final say.
Foster,Dawson,McAuley, Olsson,Evans (Gardner 53), Yacob,Sandro (Anichebe 69), Sessegnon (Berahino 62), Fletcher, McClean, Rondon.
Fabianski,Rangel,Fernandez,Williams, Taylor (Naughton 59),Cork,Britton,Ki (Paloschi 45), Ayew (Amat 82),Sigurdsson,Routledge.