The same rule applies to the tender of performance: if the offer invites acceptance either by a performance or by a promise, then tendering or beginning performance is acceptance by performance of the offer, where the tendering or beginning of the performance is a promise to complete the performance. See Restatement (Second) Contracts ยง 62.
To tender performance is to attempt to provide the performance invited by the offer. For example, if Jones has a contract with Smith to deliver hula hoops to Smith, Jones tenders performance when she arrives at Smith's loading dock prepared to unload the goods.