Hernandez's lawyer responded by aggressively questioning Kwami Nicholas, bringing up inconsistencies in what he told police and what he said on the stand.
Hernandez has pleaded not guilty in the June 17, 2013, killing of Odin Lloyd, who was dating the sister of Hernandez's fiancee.
Nicholas testified that he went to Rumor nightclub with several of Lloyd's friends around 11 p.m. on June 14, and stayed until it closed around 2 a.m. His cousin, Jules Nesbit, was a friend of Lloyd's.
Nicholas said Hernandez was also there, and he saw him after the DJ announced the Patriots star was in the club. Previous testimony has established that Hernandez went to the club with Lloyd and another man, whom prosecutors have identified as Hernandez's barber, Roberto Olivares.
In an August 2013 interview with police that was played by the defence team, a police officer asks if he knew what Hernandez looked like before that night.
"I'm a Patriots fan," he replied with a shrug.
Under questioning by prosecutors, Nicholas said he saw Hernandez about 10 to 15 feet away, staring at Odin and another friend. He said Hernandez looked like he was angry, upset and tense.
"Like something was up," he said.
The description was stricken by the judge after the defence objected.
When they left the club, Nicholas testified, he saw Hernandez "storming out of the club" and "walking real fast with his head down."
He said Lloyd ran to chase him but that Hernandez brushed him off.
Defence lawyer Michael Fee went after Nicholas's testimony, repeatedly playing video clips from the 2013 police interview in which his testimony varied, such as about where Hernandez was and what Hernandez was doing or could see at the club.
He also questioned Nicholas' opinion of Hernandez's mood. Nicholas acknowledged he had never met Hernandez before and had never seen him leave a club.
"You're not familiar with Aaron's expressions and what he does with his face?" Fee asked.
"I'm familiar with human expressions," Nicholas replied.
"You have no familiarity with Aaron's face or his expressions, do you?" Fee asked again.
"No, I don't," Nicholas acknowledged.
Associated Press writer Mark Pratt in Boston contributed to this report.